Brings the app-use feature (OPENSWARM_APP bridge, AppAgent delegation tool,
BrowserClickPoint, autopilot supervision) onto the linted eric/dev base.
- Resolved 9 conflicts favoring eric's refactored structure; renamed all of
pierre's _-prefixed names to p_/P_, kept eric's prior_messages resume guard.
- Made the 4 test-exercised bridge helpers public (p-private rule).
- Wired AppAgent into browser_delegation_tools + BuiltinTool registry and
threaded selected_app_output_ids -> OPENSWARM_SELECTED_APP_IDS (eric had
forward-ported the prompt but not the tool, so it was unreachable).
- Linter clean (underscore/p-private/ruff/cycles 0); 301 backend tests pass.