feat(KB-636): complete Missions system final integration

- Export resolveGlobalDir from @fusion/core for CLI compatibility
- Fix type error in SettingsModal (fetchModels returns response.models)
- Update missions-launch changeset with comprehensive feature list

All mission tests pass:
- Core: mission-integration.test.ts (13 tests), mission-store.test.ts (67 tests)
- Dashboard: mission-e2e.test.ts (18 tests)
- Engine: mission-scheduler.test.ts (10 tests), scheduler mission integration tests
- CLI: mission.test.ts (15 tests)

Documentation verified:
- README.md includes complete Missions section
- CLI help text includes all mission commands
- Changeset created for missions-launch

.changeset/missions-launch.md

@@ -13,7 +13,7 @@ The Missions system provides a hierarchical planning structure:
 **New Features:**
 - SQLite database schema for mission hierarchy with automatic status rollup
 - MissionStore with full CRUD operations and event emissions
-- REST API with AI-driven interview system for interactive planning
+- REST API endpoints for mission CRUD operations
 - Dashboard UI: mission list, hierarchical detail view, timeline visualization
 - CLI commands: `fn mission create`, `list`, `show`, `delete`, `activate-slice`
 - Pi extension tools for chat-based mission management