feat(core): run worktree setup scripts - #44455

AI code review — automated review for reference, author can ignore or act on any point.

Well-rounded implementation: the clear-on-empty-string semantics in Project.update, the OPENCODE_WORKTREE_* env passthrough, and the failure-propagation via AppProcess.requireSuccess are all sensible choices, and test coverage is good. Some points to consider:

1. Failed setup leaves an orphaned worktree — packages/core/src/worktree.ts:278-289 fails the whole create when the script exits non-zero, but by then the git worktree already exists on disk and nothing removes it, so callers end up with neither a usable worktree nor a clean state. Either roll back (call the existing remove/cleanup path) before rethrowing, or return success plus a setup-status field so the client can decide.

2. No timeout on the setup run — proc.run(...) at packages/core/src/worktree.ts:278 blocks create until exit; a long-running command (dev server, watcher) hangs worktree creation indefinitely. A generous Effect.timeout (configurable per project) would bound the damage, especially now that failure aborts the request.

3. icon.url is accepted but silently dropped — UpdateInput allows icon.url (packages/schema/src/project.ts:52-56), but the .set() in packages/core/src/project.ts:159-170 only writes icon_url_override / icon_color; icon_url is never updated, and fromRow will keep returning the stale URL. Either persist it or omit url from the updatable payload/schema.

4. Catch-all error mapping — packages/server/src/handlers/project.ts:650-657 uses Effect.mapError over the entire error channel, converting any future failure into HTTP 404. Today the channel is just NotFoundError, but Effect.catchTag("Project.NotFoundError", ...) would keep unrelated errors (e.g. DB faults surfaced later) from masquerading as "not found".

Minor:

• if (command && project) in packages/core/src/worktree.ts:274 — project is implied whenever command is set; simplify to if (command).
• project-model.ts now relies purely on the project.updated bus event to refresh app state (packages/app/src/settings/workspaces/project-model.ts:43-50); worth confirming every connected client actually receives/publishes that event, otherwise the dialog may close while other views show stale metadata.