Fix workspace deletion — use build transition API

The plain DELETE endpoint returns 405 for stopped workspaces. Use
POST /workspaces/:id/builds with {"transition":"delete"} instead,
which is the correct Coder API for workspace deletion.

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

src/queue.ts

@@ -158,7 +158,7 @@ export class TaskQueue {
         "create-workspace",
         { task, comment },
         {
-          jobId: `create:${key}`,
+          jobId: `create-${key}`,
           attempts: 3,
           backoff: { type: "exponential", delay: 5000 },
         },
@@ -198,7 +198,7 @@ export class TaskQueue {
       "cleanup-workspace",
       { workspaceId: entry.workspaceId, workspaceName: entry.workspaceName },
       {
-        jobId: `cleanup:${workspaceName}`,
+        jobId: `cleanup-${workspaceName}`,
         attempts: 5,
         backoff: { type: "exponential", delay: 10000 },
       },
@@ -308,7 +308,7 @@ export class TaskQueue {
               "cleanup-workspace",
               { workspaceId: ws.id, workspaceName: ws.name },
               {
-                jobId: `cleanup:stale-${ws.name}-${Date.now()}`,
+                jobId: `cleanup-stale-${ws.name}-${Date.now()}`,
                 attempts: 5,
                 backoff: { type: "exponential", delay: 10000 },
               },

src/services/coder.ts

@@ -109,12 +109,14 @@ export class CoderClient {
 
   async deleteWorkspace(workspaceId: string): Promise<void> {
     const res = await fetch(
-      `${this.baseUrl}/api/v2/workspaces/${workspaceId}`,
+      `${this.baseUrl}/api/v2/workspaces/${workspaceId}/builds`,
       {
-        method: "DELETE",
+        method: "POST",
         headers: {
+          "Content-Type": "application/json",
           "Coder-Session-Token": this.token,
         },
+        body: JSON.stringify({ transition: "delete" }),
       },
     );