merge: integrate origin/dev into modular-enforcement branch

Resolves all merge conflicts, preserving our split module structure
while integrating all dev changes:
- Custom agent summaries support (parseRegisteredAgentSummaries)
- Background notification queue (enqueueNotificationForParent)
- Atlas shared git-worktree module (collectGitDiffStats, formatFileChanges)
- Ralph-loop withTimeout + DEFAULT_API_TIMEOUT=5000
- Session recovery assistant_prefill_unsupported error type
- Atlas agentOverrides forwarding
- Config handler plan model demotion (buildPlanDemoteConfig)
- Delegate-task agentOverrides, promptSyncWithModelSuggestionRetry, variant
- LSP init timeout + stale init detection
- isPlanFamily function + task-continuation-enforcer hook
- Handoff command

src/tools/lsp/lsp-manager-process-cleanup.ts

@@ -0,0 +1,45 @@
+type ManagedClientForCleanup = {
+  client: {
+    stop: () => Promise<void>
+  }
+}
+
+type ProcessCleanupOptions = {
+  getClients: () => IterableIterator<[string, ManagedClientForCleanup]>
+  clearClients: () => void
+  clearCleanupInterval: () => void
+}
+
+export function registerLspManagerProcessCleanup(options: ProcessCleanupOptions): void {
+  // Synchronous cleanup for 'exit' event (cannot await)
+  const syncCleanup = () => {
+    for (const [, managed] of options.getClients()) {
+      try {
+        // Fire-and-forget during sync exit - process is terminating
+        void managed.client.stop().catch(() => {})
+      } catch {}
+    }
+    options.clearClients()
+    options.clearCleanupInterval()
+  }
+
+  // Async cleanup for signal handlers - properly await all stops
+  const asyncCleanup = async () => {
+    const stopPromises: Promise<void>[] = []
+    for (const [, managed] of options.getClients()) {
+      stopPromises.push(managed.client.stop().catch(() => {}))
+    }
+    await Promise.allSettled(stopPromises)
+    options.clearClients()
+    options.clearCleanupInterval()
+  }
+
+  process.on("exit", syncCleanup)
+
+  // Don't call process.exit() here; other handlers (background-agent manager) handle final exit.
+  process.on("SIGINT", () => void asyncCleanup().catch(() => {}))
+  process.on("SIGTERM", () => void asyncCleanup().catch(() => {}))
+  if (process.platform === "win32") {
+    process.on("SIGBREAK", () => void asyncCleanup().catch(() => {}))
+  }
+}