Add task queue with dedup and concurrency control

- Tasks keyed by {taskType}-{repo}-{issue} for deduplication
- Duplicate requests (pending or running) are dropped
- Configurable concurrency via QUEUE_CONCURRENCY env (default 2)
- Workspace names now {taskType}-{repo}-{issue} for observability
- GET /queue endpoint shows pending/running tasks
- All handlers route through the queue instead of calling Coder directly

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

src/handlers/release.ts

@@ -1,7 +1,6 @@
 import type { Context } from "hono";
 import type { IssueEvent, TaskRequest } from "../types.js";
-import type { CoderClient } from "../services/coder.js";
-import type { GiteaClient } from "../services/gitea.js";
+import type { TaskQueue } from "../queue.js";
 import type { Config } from "../config.js";
 
 /**
@@ -10,7 +9,7 @@ import type { Config } from "../config.js";
  *
  * Replaces: release-process.json
  */
-export function release(config: Config, coder: CoderClient, gitea: GiteaClient) {
+export function release(config: Config, queue: TaskQueue) {
   return async (c: Context) => {
     const event = await c.req.json<IssueEvent>();
 
@@ -52,18 +51,11 @@ export function release(config: Config, coder: CoderClient, gitea: GiteaClient)
       giteaToken: config.giteaDevToken,
     };
 
-    console.log(`[release] #${task.issueNumber} → release`);
+    const queued = queue.enqueue(task, {
+      useReviewAccount: false,
+      body: `🤖 Release process started.`,
+    });
 
-    const workspace = await coder.createWorkspace(task);
-    console.log(`[release] workspace created: ${workspace.name}`);
-
-    await gitea.commentOnIssue(
-      org,
-      repo,
-      event.issue.number,
-      `🤖 Release process started.`,
-    );
-
-    return c.json({ ok: true, workspace: workspace.name });
+    return c.json({ ok: true, queued });
   };
 }