feat(KB-620): add multi-project migration and first-run experience

- Add FirstRunDetector for fresh-install and migration state detection
- Implement MigrationOrchestrator for auto-registering existing projects
- Create BackwardCompat layer to maintain single-project CLI workflows
- Add fn init command for manual project registration
- Add dashboard first-run wizard API endpoints (/api/setup-state, /api/complete-setup)
- Add runtimeLog, ipcLog, projectManagerLog, hybridExecutorLog to engine logger
- Include changeset documenting migration features and rollback procedure

packages/engine/src/logger.ts

@@ -64,3 +64,15 @@ export const reviewerLog = createLogger("reviewer");
 
 /** Logger for the PR monitor subsystem. */
 export const prMonitorLog = createLogger("pr-monitor");
+
+/** Logger for the project runtime subsystem. */
+export const runtimeLog = createLogger("runtime");
+
+/** Logger for the IPC subsystem. */
+export const ipcLog = createLogger("ipc");
+
+/** Logger for the project manager subsystem. */
+export const projectManagerLog = createLogger("project-manager");
+
+/** Logger for the hybrid executor subsystem. */
+export const hybridExecutorLog = createLogger("hybrid-executor");