feat(gitlab): add GraphQL client with adaptive pagination and work item status types

Introduce a reusable GraphQL client (`src/gitlab/graphql.rs`) that handles
GitLab's GraphQL API with full error handling for auth failures, rate
limiting, and partial errors. Key capabilities:

- Adaptive page sizing (100 → 50 → 25 → 10) to handle GitLab GraphQL
  complexity limits without hardcoding a single safe page size
- Paginated issue status fetching via the workItems GraphQL query
- Graceful detection of unsupported instances (missing GraphQL endpoint
  or forbidden auth) so ingestion continues without status data
- Retry-After header parsing via the `httpdate` crate for rate limit
  compliance

Also adds `WorkItemStatus` type to `gitlab::types` with name, category,
color, and icon_name fields (all optional except name) with comprehensive
deserialization tests covering all system statuses (TO_DO, IN_PROGRESS,
DONE, CANCELED) and edge cases (null category, unknown future values).

The `GitLabClient` gains a `graphql_client()` factory method for
ergonomic access from the ingestion pipeline.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Cargo.lock

@@ -1118,6 +1118,7 @@ dependencies = [
  "dirs",
  "flate2",
  "futures",
+ "httpdate",
  "indicatif",
  "libc",
  "open",

Cargo.toml

@@ -45,6 +45,7 @@ rand = "0.8"
 sha2 = "0.10"
 flate2 = "1"
 chrono = { version = "0.4", features = ["serde"] }
+httpdate = "1"
 uuid = { version = "1", features = ["v4"] }
 regex = "1"
 strsim = "0.11"

src/gitlab/client.rs

@@ -95,6 +95,10 @@ impl GitLabClient {
         }
     }
 
+    pub fn graphql_client(&self) -> crate::gitlab::graphql::GraphqlClient {
+        crate::gitlab::graphql::GraphqlClient::new(&self.base_url, &self.token)
+    }
+
     pub async fn get_current_user(&self) -> Result<GitLabUser> {
         self.request("/api/v4/user").await
     }

src/gitlab/mod.rs

@@ -1,4 +1,5 @@
 pub mod client;
+pub mod graphql;
 pub mod transformers;
 pub mod types;
 
@@ -10,5 +11,5 @@ pub use transformers::{
 pub use types::{
     GitLabAuthor, GitLabDiscussion, GitLabIssue, GitLabIssueRef, GitLabLabelEvent, GitLabLabelRef,
     GitLabMergeRequestRef, GitLabMilestoneEvent, GitLabMilestoneRef, GitLabMrDiff, GitLabNote,
-    GitLabNotePosition, GitLabProject, GitLabStateEvent, GitLabUser, GitLabVersion,
+    GitLabNotePosition, GitLabProject, GitLabStateEvent, GitLabUser, GitLabVersion, WorkItemStatus,
 };

src/gitlab/types.rs

@@ -262,3 +262,86 @@ pub struct GitLabMergeRequest {
     pub merge_commit_sha: Option<String>,
     pub squash_commit_sha: Option<String>,
 }
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct WorkItemStatus {
+    pub name: String,
+    pub category: Option<String>,
+    pub color: Option<String>,
+    #[serde(rename = "iconName")]
+    pub icon_name: Option<String>,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_work_item_status_deserialize() {
+        let json = r##"{"name":"In progress","category":"IN_PROGRESS","color":"#1f75cb","iconName":"status-in-progress"}"##;
+        let status: WorkItemStatus = serde_json::from_str(json).unwrap();
+        assert_eq!(status.name, "In progress");
+        assert_eq!(status.category.as_deref(), Some("IN_PROGRESS"));
+        assert_eq!(status.color.as_deref(), Some("#1f75cb"));
+        assert_eq!(status.icon_name.as_deref(), Some("status-in-progress"));
+    }
+
+    #[test]
+    fn test_work_item_status_optional_fields() {
+        let json = r#"{"name":"To do"}"#;
+        let status: WorkItemStatus = serde_json::from_str(json).unwrap();
+        assert_eq!(status.name, "To do");
+        assert!(status.category.is_none());
+        assert!(status.color.is_none());
+        assert!(status.icon_name.is_none());
+    }
+
+    #[test]
+    fn test_work_item_status_unknown_category() {
+        let json = r#"{"name":"Custom","category":"SOME_FUTURE_VALUE"}"#;
+        let status: WorkItemStatus = serde_json::from_str(json).unwrap();
+        assert_eq!(status.category.as_deref(), Some("SOME_FUTURE_VALUE"));
+    }
+
+    #[test]
+    fn test_work_item_status_null_category() {
+        let json = r#"{"name":"In progress","category":null}"#;
+        let status: WorkItemStatus = serde_json::from_str(json).unwrap();
+        assert!(status.category.is_none());
+    }
+
+    #[test]
+    fn test_work_item_status_all_system_statuses() {
+        let cases = [
+            (
+                r##"{"name":"To do","category":"TO_DO","color":"#737278"}"##,
+                "TO_DO",
+            ),
+            (
+                r##"{"name":"In progress","category":"IN_PROGRESS","color":"#1f75cb"}"##,
+                "IN_PROGRESS",
+            ),
+            (
+                r##"{"name":"Done","category":"DONE","color":"#108548"}"##,
+                "DONE",
+            ),
+            (
+                r##"{"name":"Won't do","category":"CANCELED","color":"#DD2B0E"}"##,
+                "CANCELED",
+            ),
+            (
+                r##"{"name":"Duplicate","category":"CANCELED","color":"#DD2B0E"}"##,
+                "CANCELED",
+            ),
+        ];
+        for (json, expected_cat) in cases {
+            let status: WorkItemStatus = serde_json::from_str(json).unwrap();
+            assert_eq!(
+                status.category.as_deref(),
+                Some(expected_cat),
+                "Failed for: {}",
+                status.name
+            );
+        }
+    }
+}