feat: Add remote sync for project clones

Fetch remote changes before agents start working so they build on
up-to-date code. Adds ProjectSyncManager with git fetch + ff-only
merge of defaultBranch, integrated into phase dispatch to sync
before branch creation.

- Schema: lastFetchedAt column on projects table (migration 0029)
- Events: project:synced, project:sync_failed
- Phase dispatch: sync all linked projects before creating branches
- tRPC: syncProject, syncAllProjects, getProjectSyncStatus
- CLI: cw project sync [name] --all, cw project status [name]
- Frontend: sync button + ahead/behind badge on projects settings

apps/server/drizzle/meta/_journal.json

@@ -197,6 +197,20 @@
       "when": 1771891200000,
       "tag": "0027_add_chat_sessions",
       "breakpoints": true
+    },
+    {
+      "idx": 28,
+      "version": "6",
+      "when": 1771977600000,
+      "tag": "0028_add_review_comments",
+      "breakpoints": true
+    },
+    {
+      "idx": 29,
+      "version": "6",
+      "when": 1772064000000,
+      "tag": "0029_add_project_last_fetched_at",
+      "breakpoints": true
     }
   ]
 }