fix(haivemind): restore deferred startup

Start engine only after MainScreen mounts, while preserving explicit MainScreen widget lookup.

.beads/issues.jsonl

@@ -1,3 +1,4 @@
+{"_type":"issue","id":"nix-overlay-a9m","title":"Fix haivemind startup after MainScreen mount","description":"Restore deferred engine startup while preserving MainScreen widget lookup fix.","status":"closed","priority":1,"issue_type":"bug","assignee":"Alexander Miroshnichenko","owner":"alex@millerson.name","created_at":"2026-08-20T11:20:36Z","created_by":"Alexander Miroshnichenko","updated_at":"2026-08-20T11:21:43Z","started_at":"2026-08-20T11:20:43Z","closed_at":"2026-08-20T11:21:43Z","close_reason":"Restored engine startup after MainScreen mount and verified package build.","dependency_count":0,"dependent_count":0,"comment_count":0}
 {"_type":"issue","id":"nix-overlay-q00","title":"Add haivemind package","description":"Package https://github.com/dev-boz/haivemind in the Nix overlay, document it, validate the build, and complete repository workflow.","status":"closed","priority":2,"issue_type":"task","assignee":"Alexander Miroshnichenko","owner":"alex@millerson.name","created_at":"2026-08-08T16:32:37Z","created_by":"Alexander Miroshnichenko","updated_at":"2026-08-08T16:36:41Z","started_at":"2026-08-08T16:33:00Z","closed_at":"2026-08-08T16:36:41Z","close_reason":"Closed","dependency_count":0,"dependent_count":0,"comment_count":0}
 {"_type":"issue","id":"nix-overlay-67e","title":"Add traycer package","description":"Add new package for traycer from https://github.com/traycerai/traycer. Steps: research repo build system, create packages/traycer/, stage with git add, test nix build, update README.","status":"closed","priority":2,"issue_type":"task","assignee":"Alexander Miroshnichenko","owner":"alex@millerson.name","created_at":"2026-08-07T08:59:25Z","created_by":"Alexander Miroshnichenko","updated_at":"2026-08-07T09:22:07Z","started_at":"2026-08-07T09:00:29Z","closed_at":"2026-08-07T09:22:07Z","close_reason":"Traycer package added, built, pushed","dependency_count":0,"dependent_count":0,"comment_count":0}
 {"_type":"issue","id":"nix-overlay-2gf","title":"Update all packages to latest versions","description":"## Why\\nUser request: update every package in the overlay to its latest upstream version.\\n\\n## What\\nBump version + src hash (and cargoHash for Rust) in each packages/\u003cname\u003e/package.nix, update README table if needed, verify builds.\\n\\n## Acceptance\\n- Every package builds with nix build .#\u003cname\u003e\\n- README reflects new versions\\n- Changes committed and pushed","notes":"All packages updated and built successfully. Commit 1f3f0f468bdd on local main. PUSH BLOCKED: git.millerson.name:22002 and DoltHub unreachable from this network (SSH connect timeout). Re-run git push + bd dolt push when network is back, then close.","status":"closed","priority":2,"issue_type":"task","assignee":"Alexander Miroshnichenko","owner":"alex@millerson.name","created_at":"2026-08-07T07:22:50Z","created_by":"Alexander Miroshnichenko","updated_at":"2026-08-07T13:17:34Z","started_at":"2026-08-07T07:22:55Z","closed_at":"2026-08-07T13:17:34Z","close_reason":"All packages updated to latest versions, verified building, pushed to origin","dependency_count":0,"dependent_count":0,"comment_count":0}

packages/haivemind/fix-chat-log-race.patch

@@ -1,5 +1,14 @@
 --- a/haivemind_tui.py
 +++ b/haivemind_tui.py
+@@ -1197,0 +1198,8 @@
++    def on_mount(self) -> None:
++        app = self.app
++        if (
++            getattr(app, "_prompt", None) is not None
++            and getattr(app, "_config", None) is not None
++        ):
++            app.start_run(app._prompt, app._config)
++
 @@ -1220,13 +1220,13 @@
          self._engine: HaivemindEngine | None = None
          self._run_started = False