refactor: address review feedback on stale-worktree fix

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

Author: centdix

backend/src/adapters/git.ts

@@ -96,7 +96,7 @@ function spawnGit(args: string[], cwd: string): { ok: true; result: Bun.SyncSubp
     };
   } catch (error) {
     // Bun.spawnSync throws synchronously when cwd doesn't exist (posix_spawn ENOENT).
-    return { ok: false, stderr: `spawn failed (cwd=${cwd}): ${errorMessage(error)}` };
+    return { ok: false, stderr: `spawn error (cwd=${cwd}): ${errorMessage(error)}` };
   }
 }
 

backend/src/services/lifecycle-service.ts

@@ -517,6 +517,9 @@ export class LifecycleService {
   }
 
   private listCheckedOutBranches(): Set<string> {
+    // Raw listWorktrees on purpose: a stale registration still holds its branch
+    // in git's view, so it must continue to block branch reuse. Switching this
+    // to listLiveWorktrees would falsely report the branch as free.
     return new Set(
       this.deps.git.listWorktrees(resolve(this.deps.projectRoot))
         .filter((entry): entry is GitWorktreeEntry & { branch: string } => !entry.bare && entry.branch !== null)

backend/src/services/linear-auto-create-service.ts

@@ -45,6 +45,9 @@ async function runAutoCreate(deps: LinearAutoCreateDependencies): Promise<void>
   }
 
   const projectRoot = deps.projectRoot;
+  // Raw listWorktrees on purpose: a stale registration still holds its branch
+  // in git's view, so we must treat it as taken to avoid re-creating a worktree
+  // for an already-registered branch. listLiveWorktrees would skip it.
   const existingBranches = deps.git
     .listWorktrees(projectRoot)
     .filter((entry) => !entry.bare && entry.branch !== null)