Route spec PR review feedback to rework-spec instead of rework-pr

When a review requests changes on a docs/ branch (architect PR), trigger
the rework-spec task type instead of rework-pr. This re-runs the architect
persona to fix the design docs based on review feedback.

- Add rework-spec to Coder template task_type options and lightweight stages
- Detect architect PRs via docs/ branch prefix in pr-rework handler

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

src/handlers/pr-rework.ts

@@ -26,9 +26,11 @@ export function prRework(config: Config, queue: TaskQueue) {
 
     let taskType: string | null = null;
     let giteaToken: string;
+    const branch = event.pull_request.head.ref;
+    const isArchitectPR = branch.startsWith("docs/");
 
     if (reviewState === "request_changes") {
-      taskType = "rework-pr";
+      taskType = isArchitectPR ? "rework-spec" : "rework-pr";
       giteaToken = config.giteaDevToken;
     } else if (reviewState === "approved") {
       taskType = "test";