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

packages/core/src/index.ts

@@ -6,7 +6,7 @@ export { TaskStore } from "./store.js";
 export { Database, createDatabase, toJson, toJsonNullable, fromJson } from "./db.js";
 export type { Statement } from "./db.js";
 export { detectLegacyData, migrateFromLegacy, getMigrationStatus } from "./db-migrate.js";
-export { GlobalSettingsStore } from "./global-settings.js";
+export { GlobalSettingsStore, resolveGlobalDir } from "./global-settings.js";
 export { canTransition, getValidTransitions, resolveDependencyOrder } from "./board.js";
 export { 
   isGhAvailable, 

packages/dashboard/app/components/SettingsModal.tsx

@@ -140,7 +140,7 @@ export function SettingsModal({
     if (activeSection === "default-model" || activeSection === "execution-model") {
       setModelsLoading(true);
       fetchModels()
-        .then((models) => setAvailableModels(models))
+        .then((response) => setAvailableModels(response.models))
         .catch(() => setAvailableModels([]))
         .finally(() => setModelsLoading(false));
     }