fix: review hardening — full push-range diff, fail-closed diff fetch, crash-safe queue, 403 self-heal

- push reviews now fetch ONE compare diff (before...after) instead of
  slicing to the first 20 commits under a head-sha status; new-branch
  pushes (zero before-sha) fall back to the head commit diff
- truncated diffs can no longer yield a clean pass: verdict capped at
  warn and status description prefixed 'partial review (diff truncated)'
- any diff-fetch failure (throw / empty body on a non-empty push or PR)
  short-circuits to status 'warning' ('review unavailable — diff fetch
  failed (not blocking)') with a ledger row; a diffless prompt is never
  sent to the model
- accepted jobs persist to sqlite (queue_jobs) before the pending status
  posts; startup re-enqueues rows that never reached a final state, so
  restarts no longer strand shas at 'pending'
- 403 on status/comment posts self-heals: admin-scoped token (config
  admin_token) adds shre-reviewer as collaborator (write), retries once
- scripts/wire-repos.mjs: idempotent estate-wide webhook + collaborator
  wiring over GET /repos/search
- tests: 32 -> 51 (truncation cap, persisted-queue reconciliation,
  collab-retry stubs, fetchDiff routing)

Co-Authored-By: Claude Fable 5 <[email protected]>

test/access.test.js

@@ -0,0 +1,84 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { withCollabRetry } from '../src/lib/access.js';
+
+const err = (status, msg = `http ${status}`) => Object.assign(new Error(msg), { status });
+const noLog = () => {};
+
+function adminStub() {
+  const calls = [];
+  return {
+    calls,
+    addCollaborator(owner, repo, username, permission) {
+      calls.push({ owner, repo, username, permission });
+      return Promise.resolve();
+    }
+  };
+}
+
+test('403 adds collaborator (write) then retries once and succeeds', async () => {
+  const admin = adminStub();
+  let attempts = 0;
+  const out = await withCollabRetry(async () => {
+    attempts++;
+    if (attempts === 1) throw err(403);
+    return 'ok';
+  }, { adminGitea: admin, owner: 'nirpa', repo: 'newrepo', botUsername: 'shre-reviewer', log: noLog });
+  assert.equal(out, 'ok');
+  assert.equal(attempts, 2);
+  assert.deepEqual(admin.calls, [{ owner: 'nirpa', repo: 'newrepo', username: 'shre-reviewer', permission: 'write' }]);
+});
+
+test('non-403 errors are rethrown without touching collaborators', async () => {
+  const admin = adminStub();
+  await assert.rejects(
+    () => withCollabRetry(() => Promise.reject(err(500)), {
+      adminGitea: admin, owner: 'o', repo: 'r', botUsername: 'b', log: noLog
+    }),
+    /http 500/
+  );
+  assert.equal(admin.calls.length, 0);
+});
+
+test('403 with no admin client rethrows the original 403', async () => {
+  await assert.rejects(
+    () => withCollabRetry(() => Promise.reject(err(403)), {
+      adminGitea: null, owner: 'o', repo: 'r', botUsername: 'b', log: noLog
+    }),
+    (e) => e.status === 403
+  );
+});
+
+test('retry happens exactly once: second 403 propagates', async () => {
+  const admin = adminStub();
+  let attempts = 0;
+  await assert.rejects(
+    () => withCollabRetry(() => { attempts++; return Promise.reject(err(403)); }, {
+      adminGitea: admin, owner: 'o', repo: 'r', botUsername: 'b', log: noLog
+    }),
+    (e) => e.status === 403
+  );
+  assert.equal(attempts, 2);
+  assert.equal(admin.calls.length, 1);
+});
+
+test('addCollaborator failure propagates (no infinite loop)', async () => {
+  const admin = {
+    addCollaborator: () => Promise.reject(err(422, 'bad permission'))
+  };
+  let attempts = 0;
+  await assert.rejects(
+    () => withCollabRetry(() => { attempts++; return Promise.reject(err(403)); }, {
+      adminGitea: admin, owner: 'o', repo: 'r', botUsername: 'b', log: noLog
+    }),
+    /bad permission/
+  );
+  assert.equal(attempts, 1);
+});
+
+test('success path never consults the admin client', async () => {
+  const out = await withCollabRetry(() => Promise.resolve(42), {
+    adminGitea: undefined, owner: 'o', repo: 'r', botUsername: 'b', log: noLog
+  });
+  assert.equal(out, 42);
+});