feat(client): Add Resource Events API endpoints with generic paginated fetcher

Extends GitLabClient with methods for fetching resource events from
GitLab's per-entity API endpoints. Adds a new impl block containing:

- fetch_all_pages<T>: Generic paginated collector that handles
  x-next-page header parsing with fallback to page-size heuristics.
  Uses per_page=100 and respects the existing rate limiter via
  request_with_headers. Terminates when: (a) x-next-page header is
  absent/stale, (b) response is empty, or (c) page is not full.

- Six typed endpoint methods:
  - fetch_issue_state_events / fetch_mr_state_events
  - fetch_issue_label_events / fetch_mr_label_events
  - fetch_issue_milestone_events / fetch_mr_milestone_events

- fetch_all_resource_events: Convenience method that fetches all three
  event types for an entity (issue or merge_request) in sequence,
  returning a tuple of (state, label, milestone) event vectors.
  Routes to issue or MR endpoints based on entity_type string.

All methods follow the existing client patterns: path formatting with
gitlab_project_id and iid, error propagation via Result, and rate
limiter integration through the shared request_with_headers path.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/gitlab/client.rs

@@ -13,7 +13,8 @@ use tokio::time::sleep;
 use tracing::debug;
 
 use super::types::{
-    GitLabDiscussion, GitLabIssue, GitLabMergeRequest, GitLabProject, GitLabUser, GitLabVersion,
+    GitLabDiscussion, GitLabIssue, GitLabLabelEvent, GitLabMergeRequest, GitLabMilestoneEvent,
+    GitLabProject, GitLabStateEvent, GitLabUser, GitLabVersion,
 };
 use crate::core::error::{LoreError, Result};
 
@@ -550,6 +551,152 @@ impl GitLabClient {
     }
 }
 
+/// Resource events API methods.
+///
+/// These endpoints return per-entity events (not project-wide), so they collect
+/// all pages into a Vec rather than using streaming.
+impl GitLabClient {
+    /// Fetch all pages from a paginated endpoint, returning collected results.
+    async fn fetch_all_pages<T: serde::de::DeserializeOwned>(
+        &self,
+        path: &str,
+    ) -> Result<Vec<T>> {
+        let mut results = Vec::new();
+        let mut page = 1u32;
+        let per_page = 100u32;
+
+        loop {
+            let params = vec![
+                ("per_page", per_page.to_string()),
+                ("page", page.to_string()),
+            ];
+
+            let (items, headers) = self
+                .request_with_headers::<Vec<T>>(path, &params)
+                .await?;
+
+            let is_empty = items.is_empty();
+            let full_page = items.len() as u32 == per_page;
+            results.extend(items);
+
+            let next_page = headers
+                .get("x-next-page")
+                .and_then(|v| v.to_str().ok())
+                .and_then(|s| s.parse::<u32>().ok());
+
+            match next_page {
+                Some(next) if next > page => page = next,
+                _ => {
+                    if is_empty || !full_page {
+                        break;
+                    }
+                    page += 1;
+                }
+            }
+        }
+
+        Ok(results)
+    }
+
+    /// Fetch state events for an issue.
+    pub async fn fetch_issue_state_events(
+        &self,
+        gitlab_project_id: i64,
+        iid: i64,
+    ) -> Result<Vec<GitLabStateEvent>> {
+        let path = format!(
+            "/api/v4/projects/{gitlab_project_id}/issues/{iid}/resource_state_events"
+        );
+        self.fetch_all_pages(&path).await
+    }
+
+    /// Fetch label events for an issue.
+    pub async fn fetch_issue_label_events(
+        &self,
+        gitlab_project_id: i64,
+        iid: i64,
+    ) -> Result<Vec<GitLabLabelEvent>> {
+        let path = format!(
+            "/api/v4/projects/{gitlab_project_id}/issues/{iid}/resource_label_events"
+        );
+        self.fetch_all_pages(&path).await
+    }
+
+    /// Fetch milestone events for an issue.
+    pub async fn fetch_issue_milestone_events(
+        &self,
+        gitlab_project_id: i64,
+        iid: i64,
+    ) -> Result<Vec<GitLabMilestoneEvent>> {
+        let path = format!(
+            "/api/v4/projects/{gitlab_project_id}/issues/{iid}/resource_milestone_events"
+        );
+        self.fetch_all_pages(&path).await
+    }
+
+    /// Fetch state events for a merge request.
+    pub async fn fetch_mr_state_events(
+        &self,
+        gitlab_project_id: i64,
+        iid: i64,
+    ) -> Result<Vec<GitLabStateEvent>> {
+        let path = format!(
+            "/api/v4/projects/{gitlab_project_id}/merge_requests/{iid}/resource_state_events"
+        );
+        self.fetch_all_pages(&path).await
+    }
+
+    /// Fetch label events for a merge request.
+    pub async fn fetch_mr_label_events(
+        &self,
+        gitlab_project_id: i64,
+        iid: i64,
+    ) -> Result<Vec<GitLabLabelEvent>> {
+        let path = format!(
+            "/api/v4/projects/{gitlab_project_id}/merge_requests/{iid}/resource_label_events"
+        );
+        self.fetch_all_pages(&path).await
+    }
+
+    /// Fetch milestone events for a merge request.
+    pub async fn fetch_mr_milestone_events(
+        &self,
+        gitlab_project_id: i64,
+        iid: i64,
+    ) -> Result<Vec<GitLabMilestoneEvent>> {
+        let path = format!(
+            "/api/v4/projects/{gitlab_project_id}/merge_requests/{iid}/resource_milestone_events"
+        );
+        self.fetch_all_pages(&path).await
+    }
+
+    /// Fetch all three event types for an entity in one call.
+    pub async fn fetch_all_resource_events(
+        &self,
+        gitlab_project_id: i64,
+        entity_type: &str,
+        iid: i64,
+    ) -> Result<(Vec<GitLabStateEvent>, Vec<GitLabLabelEvent>, Vec<GitLabMilestoneEvent>)> {
+        match entity_type {
+            "issue" => {
+                let state = self.fetch_issue_state_events(gitlab_project_id, iid).await?;
+                let label = self.fetch_issue_label_events(gitlab_project_id, iid).await?;
+                let milestone = self.fetch_issue_milestone_events(gitlab_project_id, iid).await?;
+                Ok((state, label, milestone))
+            }
+            "merge_request" => {
+                let state = self.fetch_mr_state_events(gitlab_project_id, iid).await?;
+                let label = self.fetch_mr_label_events(gitlab_project_id, iid).await?;
+                let milestone = self.fetch_mr_milestone_events(gitlab_project_id, iid).await?;
+                Ok((state, label, milestone))
+            }
+            _ => Err(LoreError::Other(format!(
+                "Invalid entity type for resource events: {entity_type}"
+            ))),
+        }
+    }
+}
+
 /// Page result for merge request pagination.
 #[derive(Debug)]
 pub struct MergeRequestPage {