feat: v2.6 follow-ups — apps/server close-hook caller + DiffPanel staging hint (3.7)

apps/server fire-and-forgets BooCoder's Phase-3 close hooks (new coder-notify.ts, reuses BOOCODER_URL, never-rejects) on session-delete + chat archive/archive-all/delete, so warm backends + worktrees tear down immediately (idle-evict/reaper was the backstop). 3.7: BooCoder DiffPanel shows a muted one-liner when the selected provider can't see another agent's unapplied worktree edits (pure derivation from per-change agent + current provider, no new state). 6 new server tests (coder-notify); 537 server tests pass; web+server tsc/build clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/server/src/services/coder-notify.ts

@@ -0,0 +1,64 @@
+// v2.6.10 Phase 3 (server wiring) — fire-and-forget BooCoder close hooks.
+//
+// BooCoder (apps/coder, host systemd) added close hooks in
+// apps/coder/src/routes/lifecycle.ts:
+//   POST /api/chats/:chatId/close      — evict the chat's warm (chat,agent)
+//                                        backends, close its opencode session,
+//                                        mark agent_sessions closed, and remove
+//                                        the shared worktree on the last chat.
+//   POST /api/sessions/:sessionId/close — loop the chat-close path for every
+//                                        chat in the session.
+//
+// apps/server (Docker) can't see the host worktree dirs or reach the warm agent
+// processes, so — exactly like the existing `worktree-risk` guard in
+// routes/sessions.ts — it signals the coder over HTTP and the coder does the
+// real teardown. This call is BEST-EFFORT: the coder's idle-pool eviction and
+// the orphan-worktree reaper backstop a missed/failed call. It MUST NEVER block
+// or fail the user's delete/archive — hence fire-and-forget with a swallowed
+// catch. We do not await the returned promise at the call sites.
+
+import type { FastifyBaseLogger } from 'fastify';
+
+export type CoderCloseKind = 'chat' | 'session';
+
+function coderOrigin(): string {
+  // Same env + default as routes/sessions.ts' worktree-risk fetch.
+  return process.env.BOOCODER_URL ?? 'http://boocoder:3000';
+}
+
+/**
+ * Fire-and-forget POST to the BooCoder close hook for a chat or session.
+ *
+ * Resolves to `true` if the coder acknowledged (HTTP 2xx), `false` otherwise
+ * (non-2xx or network error). Callers SHOULD NOT await this — invoke it and
+ * move on. The returned promise never rejects: every failure path is caught,
+ * logged at debug, and folded into a `false` result so an unreachable or
+ * erroring coder can't surface to the user's delete/archive request.
+ */
+export async function notifyCoderClose(
+  kind: CoderCloseKind,
+  id: string,
+  log?: Pick<FastifyBaseLogger, 'debug'>,
+  fetcher: typeof fetch = fetch,
+): Promise<boolean> {
+  const segment = kind === 'chat' ? 'chats' : 'sessions';
+  const url = `${coderOrigin()}/api/${segment}/${id}/close`;
+  try {
+    const res = await fetcher(url, { method: 'POST' });
+    if (!res.ok) {
+      log?.debug(
+        { kind, id, status: res.status },
+        'coder close hook returned non-2xx (best-effort; reaper backstops)',
+      );
+      return false;
+    }
+    log?.debug({ kind, id }, 'coder close hook acknowledged');
+    return true;
+  } catch (err) {
+    log?.debug(
+      { kind, id, err: err instanceof Error ? err.message : String(err) },
+      'coder close hook unreachable (best-effort; reaper backstops)',
+    );
+    return false;
+  }
+}