fix(mag): guard /compact enqueue from feedback-digest throw (PR #494 review)

Wrap the tryQueueFeedbackDigest("ludics") call in magBriefing() with
try/catch so a queue-lock timeout or state-file write failure inside
the digest path can no longer suppress the unconditional /compact
enqueue. The auto-compact-after-checkpoints contract (task-a00fc0d9)
requires /compact after every briefing; the round-1 swap exposed that
contract to digest-side failures because /compact moved below the
digest call.

Add a regression test that spies on queueRequest to throw on the
feedback-digest action and asserts (a) /compact still lands in
mag/queue.jsonl as the second entry, and (b) the failure is logged.
Mutation-verified: removing the try/catch makes the new test fail.

Addresses Codex review comment on src/mag.ts:3320.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: lukstafi

src/mag-auto-compact.test.ts

@@ -1,4 +1,4 @@
-import { afterEach, beforeEach, describe, expect, test } from "bun:test";
+import { afterEach, beforeEach, describe, expect, spyOn, test } from "bun:test";
 import { mkdirSync, readFileSync, writeFileSync } from "fs";
 import { join } from "path";
 import { withSyntheticHarness } from "./test-utils.ts";
@@ -71,6 +71,48 @@ describe("magBriefing auto-compact follow-up", () => {
     expect(items[items.length - 1]!.action).toBe("message");
     expect(items[items.length - 1]!.content).toBe("/compact");
   });
+
+  test("/compact still enqueues when feedback-digest enqueue throws", async () => {
+    // Harness condition: spy on queue.queueRequest to throw on the
+    // feedback-digest action only (simulating a queue-lock timeout or
+    // state-file write failure inside tryQueueFeedbackDigest). Without the
+    // try/catch around the digest call, the throw would propagate out of
+    // magBriefing before /compact is enqueued, leaving the queue with only
+    // the briefing entry. Mutation: removing the try/catch makes this test
+    // fail because /compact never lands and `errSpy` never sees the warning.
+    const queueMod = await import("./queue.ts");
+    const origQueueRequest = queueMod.queueRequest;
+    let calls = 0;
+    const requestSpy = spyOn(queueMod, "queueRequest").mockImplementation(
+      ((req: Parameters<typeof origQueueRequest>[0]) => {
+        calls++;
+        if (req.action === "feedback-digest") {
+          throw new Error("simulated queue-lock timeout");
+        }
+        return origQueueRequest(req);
+      }) as typeof origQueueRequest,
+    );
+    const errSpy = spyOn(console, "error").mockImplementation(() => {});
+
+    try {
+      const { magBriefing } = await import("./mag.ts");
+      magBriefing(false);
+
+      const items = readQueue();
+      // briefing was queued (call 1), feedback-digest threw (call 2),
+      // /compact still queued (call 3). On disk: briefing + /compact only.
+      expect(calls).toBeGreaterThanOrEqual(3);
+      expect(items).toHaveLength(2);
+      expect(items[0]!.action).toBe("briefing");
+      expect(items[1]!.action).toBe("message");
+      expect(items[1]!.content).toBe("/compact");
+      const errLines = errSpy.mock.calls.map((c) => String(c[0] ?? ""));
+      expect(errLines.some((l) => l.includes("feedback-digest enqueue failed"))).toBe(true);
+    } finally {
+      requestSpy.mockRestore();
+      errSpy.mockRestore();
+    }
+  });
 });
 
 describe("runMag health-check auto-compact follow-up", () => {

src/mag.ts

@@ -3317,9 +3317,17 @@ export function magBriefing(wait: boolean = true, timeout: number = 300): void {
   // Auto-queue feedback-digest once daily alongside the briefing trigger.
   // Lands before /compact so digest can consume the briefing's in-flight
   // context (task-304a02a6 / docs/proposals/task-304a02a6-reorder-briefing-auto-queue.md).
-  const fdResult = tryQueueFeedbackDigest("ludics");
-  if (fdResult.queued) {
-    console.error("ludics: briefing queued feedback-digest for ludics");
+  // Wrapped so a digest enqueue failure (queue-lock timeout, state-file write
+  // error) cannot suppress the unconditional /compact below — the auto-compact
+  // contract (task-a00fc0d9) requires /compact after every briefing.
+  try {
+    const fdResult = tryQueueFeedbackDigest("ludics");
+    if (fdResult.queued) {
+      console.error("ludics: briefing queued feedback-digest for ludics");
+    }
+  } catch (err) {
+    const msg = err instanceof Error ? err.message : String(err);
+    console.error(`ludics: feedback-digest enqueue failed: ${msg}`);
   }
 
   // Auto-compact after briefing — checkpoint compaction (task-a00fc0d9 /