feat(surgical-sync): add per-IID surgical sync pipeline with preflight validation

Add the ability to sync specific issues or merge requests by IID without
running a full incremental sync. This enables fast, targeted data refresh
for individual entities — useful for agent workflows, debugging, and
real-time investigation of specific issues or MRs.

Architecture:
- New CLI flags: --issue <IID> and --mr <IID> (repeatable, up to 100 total)
  scoped to a single project via -p/--project
- Preflight phase validates all IIDs exist on GitLab before any DB writes,
  with TOCTOU-aware soft verification at ingest time
- 6-stage pipeline: preflight -> fetch -> ingest -> dependents -> docs -> embed
- Each stage is cancellation-aware via ShutdownSignal
- Dedicated SyncRunRecorder extensions track surgical-specific counters
  (issues_fetched, mrs_ingested, docs_regenerated, etc.)

New modules:
- src/ingestion/surgical.rs: Core surgical fetch/ingest/dependent logic
  with preflight_fetch(), ingest_issue_by_iid(), ingest_mr_by_iid(),
  and fetch_dependents_for_{issue,mr}()
- src/cli/commands/sync_surgical.rs: Full CLI orchestrator with progress
  spinners, human/robot output, and cancellation handling
- src/embedding/pipeline.rs: embed_documents_by_ids() for scoped embedding
- src/documents/regenerator.rs: regenerate_dirty_documents_for_sources()
  for scoped document regeneration

Database changes:
- Migration 027: Extends sync_runs with mode, phase, surgical_iids_json,
  per-entity counters, and cancelled_at column
- New indexes: idx_sync_runs_mode_started, idx_sync_runs_status_phase_started

GitLab client:
- get_issue_by_iid() and get_mr_by_iid() single-entity fetch methods

Error handling:
- New SurgicalPreflightFailed error variant with entity_type, iid, project,
  and reason fields. Shares exit code 6 with GitLabNotFound.

Includes comprehensive test coverage:
- 645 lines of surgical ingestion tests (wiremock-based)
- 184 lines of scoped embedding tests
- 85 lines of scoped regeneration tests
- 113 lines of GitLab client single-entity tests
- 236 lines of sync_run surgical column/counter tests
- Unit tests for SyncOptions, error codes, and CLI validation

src/ingestion/surgical_tests.rs

@@ -0,0 +1,645 @@
+use std::path::Path;
+
+use super::*;
+use crate::core::config::{
+    Config, EmbeddingConfig, GitLabConfig, LoggingConfig, ProjectConfig, ScoringConfig,
+    StorageConfig, SyncConfig,
+};
+use crate::core::db::{create_connection, run_migrations};
+use crate::gitlab::types::{GitLabAuthor, GitLabMergeRequest};
+
+// ---------------------------------------------------------------------------
+// Test helpers
+// ---------------------------------------------------------------------------
+
+fn setup_db() -> rusqlite::Connection {
+    let conn = create_connection(Path::new(":memory:")).expect("in-memory DB");
+    run_migrations(&conn).expect("migrations");
+    conn.execute(
+        "INSERT INTO projects (gitlab_project_id, path_with_namespace, web_url)
+         VALUES (100, 'group/repo', 'https://example.com/group/repo')",
+        [],
+    )
+    .expect("insert project");
+    conn
+}
+
+fn test_config() -> Config {
+    Config {
+        gitlab: GitLabConfig {
+            base_url: "https://gitlab.example.com".to_string(),
+            token_env_var: "GITLAB_TOKEN".to_string(),
+            token: None,
+        },
+        projects: vec![ProjectConfig {
+            path: "group/repo".to_string(),
+        }],
+        default_project: None,
+        sync: SyncConfig::default(),
+        storage: StorageConfig::default(),
+        embedding: EmbeddingConfig::default(),
+        logging: LoggingConfig::default(),
+        scoring: ScoringConfig::default(),
+    }
+}
+
+fn make_test_issue(iid: i64, updated_at: &str) -> GitLabIssue {
+    GitLabIssue {
+        id: iid * 1000, // unique gitlab_id
+        iid,
+        project_id: 100,
+        title: format!("Test issue {iid}"),
+        description: Some("Description".to_string()),
+        state: "opened".to_string(),
+        created_at: "2026-01-01T00:00:00.000+00:00".to_string(),
+        updated_at: updated_at.to_string(),
+        closed_at: None,
+        author: GitLabAuthor {
+            id: 1,
+            username: "testuser".to_string(),
+            name: "Test User".to_string(),
+        },
+        assignees: vec![],
+        labels: vec![],
+        milestone: None,
+        due_date: None,
+        web_url: format!("https://example.com/group/repo/-/issues/{iid}"),
+    }
+}
+
+fn make_test_mr(iid: i64, updated_at: &str) -> GitLabMergeRequest {
+    GitLabMergeRequest {
+        id: iid * 1000,
+        iid,
+        project_id: 100,
+        title: format!("Test MR {iid}"),
+        description: Some("MR description".to_string()),
+        state: "opened".to_string(),
+        draft: false,
+        work_in_progress: false,
+        source_branch: "feature".to_string(),
+        target_branch: "main".to_string(),
+        sha: Some("abc123".to_string()),
+        references: None,
+        detailed_merge_status: None,
+        merge_status_legacy: None,
+        created_at: "2026-01-01T00:00:00.000+00:00".to_string(),
+        updated_at: updated_at.to_string(),
+        merged_at: None,
+        closed_at: None,
+        author: GitLabAuthor {
+            id: 1,
+            username: "testuser".to_string(),
+            name: "Test User".to_string(),
+        },
+        merge_user: None,
+        merged_by: None,
+        labels: vec![],
+        assignees: vec![],
+        reviewers: vec![],
+        web_url: format!("https://example.com/group/repo/-/merge_requests/{iid}"),
+        merge_commit_sha: None,
+        squash_commit_sha: None,
+    }
+}
+
+fn get_db_updated_at_helper(conn: &rusqlite::Connection, table: &str, iid: i64) -> Option<i64> {
+    let sql = match table {
+        "issues" => "SELECT updated_at FROM issues WHERE project_id = 1 AND iid = ?1",
+        "merge_requests" => {
+            "SELECT updated_at FROM merge_requests WHERE project_id = 1 AND iid = ?1"
+        }
+        _ => return None,
+    };
+    conn.query_row(sql, [iid], |row| row.get(0)).ok()
+}
+
+fn get_dirty_keys(conn: &rusqlite::Connection) -> Vec<(String, i64)> {
+    let mut stmt = conn
+        .prepare("SELECT source_type, source_id FROM dirty_sources ORDER BY source_type, source_id")
+        .expect("prepare dirty_sources query");
+    stmt.query_map([], |row| {
+        let st: String = row.get(0)?;
+        let id: i64 = row.get(1)?;
+        Ok((st, id))
+    })
+    .expect("query dirty_sources")
+    .collect::<std::result::Result<Vec<_>, _>>()
+    .expect("collect dirty_sources")
+}
+
+// ---------------------------------------------------------------------------
+// is_stale unit tests
+// ---------------------------------------------------------------------------
+
+#[test]
+fn test_is_stale_parses_iso8601() {
+    // 2026-02-17T12:00:00.000+00:00 -> 1771243200000 ms
+    let result = is_stale("2026-02-17T12:00:00.000+00:00", Some(1_771_329_600_000));
+    assert!(result.is_ok());
+    // Same timestamp => stale
+    assert!(result.unwrap());
+}
+
+#[test]
+fn test_is_stale_handles_none_db_value() {
+    let result = is_stale("2026-02-17T12:00:00.000+00:00", None);
+    assert!(result.is_ok());
+    assert!(!result.unwrap(), "no DB row means not stale");
+}
+
+#[test]
+fn test_is_stale_with_z_suffix() {
+    let result = is_stale("2026-02-17T12:00:00Z", Some(1_771_329_600_000));
+    assert!(result.is_ok());
+    assert!(result.unwrap(), "Z suffix should parse same as +00:00");
+}
+
+// ---------------------------------------------------------------------------
+// Issue ingestion tests
+// ---------------------------------------------------------------------------
+
+#[test]
+fn test_ingest_issue_by_iid_upserts_and_marks_dirty() {
+    let conn = setup_db();
+    let config = test_config();
+    let issue = make_test_issue(42, "2026-02-17T12:00:00.000+00:00");
+
+    let result = ingest_issue_by_iid(&conn, &config, 1, &issue).unwrap();
+
+    assert!(!result.skipped_stale);
+    assert!(!result.skipped_stale);
+    assert!(!result.dirty_source_keys.is_empty());
+
+    // Verify DB row exists
+    let db_ts = get_db_updated_at_helper(&conn, "issues", 42);
+    assert!(db_ts.is_some(), "issue should exist in DB");
+
+    // Verify dirty marking
+    let dirty = get_dirty_keys(&conn);
+    assert!(
+        dirty.iter().any(|(t, _)| t == "issue"),
+        "dirty_sources should contain an issue entry"
+    );
+}
+
+#[test]
+fn test_toctou_skips_stale_issue() {
+    let conn = setup_db();
+    let config = test_config();
+    let issue = make_test_issue(42, "2026-02-17T12:00:00.000+00:00");
+
+    // First ingest succeeds
+    let r1 = ingest_issue_by_iid(&conn, &config, 1, &issue).unwrap();
+    assert!(!r1.skipped_stale);
+
+    // Clear dirty to check second ingest doesn't re-mark
+    conn.execute("DELETE FROM dirty_sources", []).unwrap();
+
+    // Second ingest with same timestamp should be skipped
+    let r2 = ingest_issue_by_iid(&conn, &config, 1, &issue).unwrap();
+    assert!(r2.skipped_stale);
+    assert!(r2.skipped_stale);
+    assert!(r2.dirty_source_keys.is_empty());
+
+    // No new dirty mark
+    let dirty = get_dirty_keys(&conn);
+    assert!(dirty.is_empty(), "stale skip should not create dirty marks");
+}
+
+#[test]
+fn test_toctou_allows_newer_issue() {
+    let conn = setup_db();
+    let config = test_config();
+
+    // Ingest at T1
+    let issue_t1 = make_test_issue(42, "2026-02-17T12:00:00.000+00:00");
+    ingest_issue_by_iid(&conn, &config, 1, &issue_t1).unwrap();
+
+    conn.execute("DELETE FROM dirty_sources", []).unwrap();
+
+    // Ingest at T2 (newer) — should succeed
+    let issue_t2 = make_test_issue(42, "2026-02-17T13:00:00.000+00:00");
+    let result = ingest_issue_by_iid(&conn, &config, 1, &issue_t2).unwrap();
+
+    assert!(!result.skipped_stale);
+    assert!(!result.skipped_stale);
+}
+
+#[test]
+fn test_ingest_issue_returns_dirty_source_keys() {
+    let conn = setup_db();
+    let config = test_config();
+    let issue = make_test_issue(42, "2026-02-17T12:00:00.000+00:00");
+
+    let result = ingest_issue_by_iid(&conn, &config, 1, &issue).unwrap();
+
+    assert_eq!(result.dirty_source_keys.len(), 1);
+    let (source_type, local_id) = &result.dirty_source_keys[0];
+    assert_eq!(source_type.as_str(), "issue");
+    assert!(*local_id > 0, "local_id should be positive");
+}
+
+#[test]
+fn test_ingest_issue_updates_existing() {
+    let conn = setup_db();
+    let config = test_config();
+
+    let issue_v1 = make_test_issue(42, "2026-02-17T12:00:00.000+00:00");
+    ingest_issue_by_iid(&conn, &config, 1, &issue_v1).unwrap();
+
+    let ts1 = get_db_updated_at_helper(&conn, "issues", 42).unwrap();
+
+    // Newer version
+    let issue_v2 = make_test_issue(42, "2026-02-17T14:00:00.000+00:00");
+    let result = ingest_issue_by_iid(&conn, &config, 1, &issue_v2).unwrap();
+
+    assert!(!result.skipped_stale);
+    let ts2 = get_db_updated_at_helper(&conn, "issues", 42).unwrap();
+    assert!(ts2 > ts1, "DB timestamp should increase after update");
+}
+
+// ---------------------------------------------------------------------------
+// MR ingestion tests
+// ---------------------------------------------------------------------------
+
+#[test]
+fn test_ingest_mr_by_iid_upserts_and_marks_dirty() {
+    let conn = setup_db();
+    let config = test_config();
+    let mr = make_test_mr(101, "2026-02-17T12:00:00.000+00:00");
+
+    let result = ingest_mr_by_iid(&conn, &config, 1, &mr).unwrap();
+
+    assert!(!result.skipped_stale);
+    assert!(!result.skipped_stale);
+    assert!(!result.dirty_source_keys.is_empty());
+
+    let db_ts = get_db_updated_at_helper(&conn, "merge_requests", 101);
+    assert!(db_ts.is_some(), "MR should exist in DB");
+
+    let dirty = get_dirty_keys(&conn);
+    assert!(
+        dirty.iter().any(|(t, _)| t == "merge_request"),
+        "dirty_sources should contain a merge_request entry"
+    );
+}
+
+#[test]
+fn test_toctou_skips_stale_mr() {
+    let conn = setup_db();
+    let config = test_config();
+    let mr = make_test_mr(101, "2026-02-17T12:00:00.000+00:00");
+
+    let r1 = ingest_mr_by_iid(&conn, &config, 1, &mr).unwrap();
+    assert!(!r1.skipped_stale);
+
+    conn.execute("DELETE FROM dirty_sources", []).unwrap();
+
+    let r2 = ingest_mr_by_iid(&conn, &config, 1, &mr).unwrap();
+    assert!(r2.skipped_stale);
+    assert!(r2.skipped_stale);
+    assert!(r2.dirty_source_keys.is_empty());
+}
+
+#[test]
+fn test_toctou_allows_newer_mr() {
+    let conn = setup_db();
+    let config = test_config();
+
+    let mr_t1 = make_test_mr(101, "2026-02-17T12:00:00.000+00:00");
+    ingest_mr_by_iid(&conn, &config, 1, &mr_t1).unwrap();
+
+    conn.execute("DELETE FROM dirty_sources", []).unwrap();
+
+    let mr_t2 = make_test_mr(101, "2026-02-17T13:00:00.000+00:00");
+    let result = ingest_mr_by_iid(&conn, &config, 1, &mr_t2).unwrap();
+
+    assert!(!result.skipped_stale);
+    assert!(!result.skipped_stale);
+}
+
+#[test]
+fn test_ingest_mr_returns_dirty_source_keys() {
+    let conn = setup_db();
+    let config = test_config();
+    let mr = make_test_mr(101, "2026-02-17T12:00:00.000+00:00");
+
+    let result = ingest_mr_by_iid(&conn, &config, 1, &mr).unwrap();
+
+    assert_eq!(result.dirty_source_keys.len(), 1);
+    let (source_type, local_id) = &result.dirty_source_keys[0];
+    assert_eq!(source_type.as_str(), "merge_request");
+    assert!(*local_id > 0);
+}
+
+#[test]
+fn test_ingest_mr_updates_existing() {
+    let conn = setup_db();
+    let config = test_config();
+
+    let mr_v1 = make_test_mr(101, "2026-02-17T12:00:00.000+00:00");
+    ingest_mr_by_iid(&conn, &config, 1, &mr_v1).unwrap();
+
+    let ts1 = get_db_updated_at_helper(&conn, "merge_requests", 101).unwrap();
+
+    let mr_v2 = make_test_mr(101, "2026-02-17T14:00:00.000+00:00");
+    let result = ingest_mr_by_iid(&conn, &config, 1, &mr_v2).unwrap();
+
+    assert!(!result.skipped_stale);
+    let ts2 = get_db_updated_at_helper(&conn, "merge_requests", 101).unwrap();
+    assert!(ts2 > ts1, "DB timestamp should increase after update");
+}
+
+// ---------------------------------------------------------------------------
+// Preflight fetch test (wiremock)
+// ---------------------------------------------------------------------------
+
+#[tokio::test]
+async fn test_preflight_fetch_returns_issues_and_mrs() {
+    use wiremock::matchers::{method, path};
+    use wiremock::{Mock, MockServer, ResponseTemplate};
+
+    let mock_server = MockServer::start().await;
+
+    // Issue fixture
+    let issue_json = serde_json::json!({
+        "id": 42000,
+        "iid": 42,
+        "project_id": 100,
+        "title": "Test issue 42",
+        "description": "desc",
+        "state": "opened",
+        "created_at": "2026-01-01T00:00:00.000+00:00",
+        "updated_at": "2026-02-17T12:00:00.000+00:00",
+        "author": {"id": 1, "username": "testuser", "name": "Test User"},
+        "assignees": [],
+        "labels": [],
+        "web_url": "https://example.com/group/repo/-/issues/42"
+    });
+
+    // MR fixture
+    let mr_json = serde_json::json!({
+        "id": 101000,
+        "iid": 101,
+        "project_id": 100,
+        "title": "Test MR 101",
+        "description": "mr desc",
+        "state": "opened",
+        "draft": false,
+        "work_in_progress": false,
+        "source_branch": "feature",
+        "target_branch": "main",
+        "sha": "abc123",
+        "created_at": "2026-01-01T00:00:00.000+00:00",
+        "updated_at": "2026-02-17T12:00:00.000+00:00",
+        "author": {"id": 1, "username": "testuser", "name": "Test User"},
+        "labels": [],
+        "assignees": [],
+        "reviewers": [],
+        "web_url": "https://example.com/group/repo/-/merge_requests/101"
+    });
+
+    Mock::given(method("GET"))
+        .and(path("/api/v4/projects/100/issues/42"))
+        .respond_with(ResponseTemplate::new(200).set_body_json(&issue_json))
+        .mount(&mock_server)
+        .await;
+
+    Mock::given(method("GET"))
+        .and(path("/api/v4/projects/100/merge_requests/101"))
+        .respond_with(ResponseTemplate::new(200).set_body_json(&mr_json))
+        .mount(&mock_server)
+        .await;
+
+    let client = GitLabClient::new(&mock_server.uri(), "test-token", None);
+    let targets = vec![
+        ("issue".to_string(), 42i64),
+        ("merge_request".to_string(), 101i64),
+    ];
+
+    let result = preflight_fetch(&client, 100, &targets).await;
+
+    assert_eq!(result.issues.len(), 1);
+    assert_eq!(result.issues[0].iid, 42);
+    assert_eq!(result.merge_requests.len(), 1);
+    assert_eq!(result.merge_requests[0].iid, 101);
+    assert!(result.failures.is_empty());
+}
+
+// ---------------------------------------------------------------------------
+// Dependent helper tests (bd-kanh)
+// ---------------------------------------------------------------------------
+
+#[tokio::test]
+async fn test_fetch_dependents_for_issue_empty_events() {
+    use wiremock::matchers::{method, path};
+    use wiremock::{Mock, MockServer, ResponseTemplate};
+
+    let mock_server = MockServer::start().await;
+    let conn = setup_db();
+    let config = test_config();
+
+    // Insert an issue so we have a local_id
+    let issue = make_test_issue(42, "2026-02-17T12:00:00.000+00:00");
+    ingest_issue_by_iid(&conn, &config, 1, &issue).unwrap();
+    let local_id: i64 = conn
+        .query_row(
+            "SELECT id FROM issues WHERE project_id = 1 AND iid = 42",
+            [],
+            |row| row.get(0),
+        )
+        .unwrap();
+
+    // Mock empty resource event endpoints
+    Mock::given(method("GET"))
+        .and(path("/api/v4/projects/100/issues/42/resource_state_events"))
+        .respond_with(ResponseTemplate::new(200).set_body_json(serde_json::json!([])))
+        .mount(&mock_server)
+        .await;
+    Mock::given(method("GET"))
+        .and(path("/api/v4/projects/100/issues/42/resource_label_events"))
+        .respond_with(ResponseTemplate::new(200).set_body_json(serde_json::json!([])))
+        .mount(&mock_server)
+        .await;
+    Mock::given(method("GET"))
+        .and(path(
+            "/api/v4/projects/100/issues/42/resource_milestone_events",
+        ))
+        .respond_with(ResponseTemplate::new(200).set_body_json(serde_json::json!([])))
+        .mount(&mock_server)
+        .await;
+
+    // Mock empty discussions endpoint
+    Mock::given(method("GET"))
+        .and(path("/api/v4/projects/100/issues/42/discussions"))
+        .respond_with(ResponseTemplate::new(200).set_body_json(serde_json::json!([])))
+        .mount(&mock_server)
+        .await;
+
+    let client = GitLabClient::new(&mock_server.uri(), "test-token", None);
+
+    let result = fetch_dependents_for_issue(&client, &conn, 1, 100, 42, local_id, &config)
+        .await
+        .unwrap();
+
+    assert_eq!(result.resource_events_fetched, 0);
+    assert_eq!(result.discussions_fetched, 0);
+}
+
+#[tokio::test]
+async fn test_fetch_dependents_for_mr_empty_events() {
+    use wiremock::matchers::{method, path};
+    use wiremock::{Mock, MockServer, ResponseTemplate};
+
+    let mock_server = MockServer::start().await;
+    let conn = setup_db();
+    let config = test_config();
+
+    // Insert an MR so we have a local_id
+    let mr = make_test_mr(101, "2026-02-17T12:00:00.000+00:00");
+    ingest_mr_by_iid(&conn, &config, 1, &mr).unwrap();
+    let local_id: i64 = conn
+        .query_row(
+            "SELECT id FROM merge_requests WHERE project_id = 1 AND iid = 101",
+            [],
+            |row| row.get(0),
+        )
+        .unwrap();
+
+    // Mock empty resource event endpoints for MR
+    Mock::given(method("GET"))
+        .and(path(
+            "/api/v4/projects/100/merge_requests/101/resource_state_events",
+        ))
+        .respond_with(ResponseTemplate::new(200).set_body_json(serde_json::json!([])))
+        .mount(&mock_server)
+        .await;
+    Mock::given(method("GET"))
+        .and(path(
+            "/api/v4/projects/100/merge_requests/101/resource_label_events",
+        ))
+        .respond_with(ResponseTemplate::new(200).set_body_json(serde_json::json!([])))
+        .mount(&mock_server)
+        .await;
+    Mock::given(method("GET"))
+        .and(path(
+            "/api/v4/projects/100/merge_requests/101/resource_milestone_events",
+        ))
+        .respond_with(ResponseTemplate::new(200).set_body_json(serde_json::json!([])))
+        .mount(&mock_server)
+        .await;
+
+    // Mock empty discussions endpoint for MR
+    Mock::given(method("GET"))
+        .and(path("/api/v4/projects/100/merge_requests/101/discussions"))
+        .respond_with(ResponseTemplate::new(200).set_body_json(serde_json::json!([])))
+        .mount(&mock_server)
+        .await;
+
+    // Mock empty closes_issues endpoint
+    Mock::given(method("GET"))
+        .and(path(
+            "/api/v4/projects/100/merge_requests/101/closes_issues",
+        ))
+        .respond_with(ResponseTemplate::new(200).set_body_json(serde_json::json!([])))
+        .mount(&mock_server)
+        .await;
+
+    // Mock empty diffs endpoint
+    Mock::given(method("GET"))
+        .and(path("/api/v4/projects/100/merge_requests/101/diffs"))
+        .respond_with(ResponseTemplate::new(200).set_body_json(serde_json::json!([])))
+        .mount(&mock_server)
+        .await;
+
+    let client = GitLabClient::new(&mock_server.uri(), "test-token", None);
+
+    let result = fetch_dependents_for_mr(&client, &conn, 1, 100, 101, local_id, &config)
+        .await
+        .unwrap();
+
+    assert_eq!(result.resource_events_fetched, 0);
+    assert_eq!(result.discussions_fetched, 0);
+    assert_eq!(result.closes_issues_stored, 0);
+    assert_eq!(result.file_changes_stored, 0);
+}
+
+#[tokio::test]
+async fn test_fetch_dependents_for_mr_with_closes_issues() {
+    use wiremock::matchers::{method, path};
+    use wiremock::{Mock, MockServer, ResponseTemplate};
+
+    let mock_server = MockServer::start().await;
+    let conn = setup_db();
+    let config = test_config();
+
+    // Insert issue and MR so references can resolve
+    let issue = make_test_issue(42, "2026-02-17T12:00:00.000+00:00");
+    ingest_issue_by_iid(&conn, &config, 1, &issue).unwrap();
+
+    let mr = make_test_mr(101, "2026-02-17T12:00:00.000+00:00");
+    ingest_mr_by_iid(&conn, &config, 1, &mr).unwrap();
+    let mr_local_id: i64 = conn
+        .query_row(
+            "SELECT id FROM merge_requests WHERE project_id = 1 AND iid = 101",
+            [],
+            |row| row.get(0),
+        )
+        .unwrap();
+
+    // Mock empty resource events
+    for endpoint in [
+        "resource_state_events",
+        "resource_label_events",
+        "resource_milestone_events",
+    ] {
+        Mock::given(method("GET"))
+            .and(path(format!(
+                "/api/v4/projects/100/merge_requests/101/{endpoint}"
+            )))
+            .respond_with(ResponseTemplate::new(200).set_body_json(serde_json::json!([])))
+            .mount(&mock_server)
+            .await;
+    }
+
+    // Mock empty discussions
+    Mock::given(method("GET"))
+        .and(path("/api/v4/projects/100/merge_requests/101/discussions"))
+        .respond_with(ResponseTemplate::new(200).set_body_json(serde_json::json!([])))
+        .mount(&mock_server)
+        .await;
+
+    // Mock closes_issues with one reference
+    Mock::given(method("GET"))
+        .and(path(
+            "/api/v4/projects/100/merge_requests/101/closes_issues",
+        ))
+        .respond_with(ResponseTemplate::new(200).set_body_json(serde_json::json!([
+            {
+                "id": 42000,
+                "iid": 42,
+                "project_id": 100,
+                "title": "Test issue 42",
+                "state": "opened",
+                "web_url": "https://example.com/group/repo/-/issues/42"
+            }
+        ])))
+        .mount(&mock_server)
+        .await;
+
+    // Mock empty diffs
+    Mock::given(method("GET"))
+        .and(path("/api/v4/projects/100/merge_requests/101/diffs"))
+        .respond_with(ResponseTemplate::new(200).set_body_json(serde_json::json!([])))
+        .mount(&mock_server)
+        .await;
+
+    let client = GitLabClient::new(&mock_server.uri(), "test-token", None);
+
+    let result = fetch_dependents_for_mr(&client, &conn, 1, 100, 101, mr_local_id, &config)
+        .await
+        .unwrap();
+
+    assert_eq!(result.closes_issues_stored, 1);
+}