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/fetchdiff.test.js

@@ -0,0 +1,66 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { fetchDiff } from '../src/lib/review.js';
+
+function giteaStub() {
+  const calls = [];
+  return {
+    calls,
+    getPrDiff: (o, r, i) => { calls.push(['pr', o, r, i]); return Promise.resolve('PRDIFF'); },
+    getCommitDiff: (o, r, sha) => { calls.push(['commit', o, r, sha]); return Promise.resolve('HEADDIFF'); },
+    getCompareDiff: (o, r, before, after) => { calls.push(['compare', o, r, before, after]); return Promise.resolve('RANGEDIFF'); }
+  };
+}
+
+const HEAD = 'a'.repeat(40);
+const BEFORE = 'b'.repeat(40);
+
+test('PR jobs use the PR diff', async () => {
+  const g = giteaStub();
+  const out = await fetchDiff({ gitea: g, job: { owner: 'o', repo: 'r', prIndex: 5, sha: HEAD, before: null } });
+  assert.equal(out, 'PRDIFF');
+  assert.deepEqual(g.calls, [['pr', 'o', 'r', 5]]);
+});
+
+test('push uses ONE compare diff over the full before...after range', async () => {
+  const g = giteaStub();
+  const out = await fetchDiff({
+    gitea: g,
+    job: {
+      owner: 'o', repo: 'r', prIndex: null, sha: HEAD, before: BEFORE,
+      // 25 commits in the payload: must NOT fall back to per-commit slicing
+      commitShas: Array.from({ length: 25 }, (_, i) => String(i).padStart(40, '0'))
+    }
+  });
+  assert.equal(out, 'RANGEDIFF');
+  assert.deepEqual(g.calls, [['compare', 'o', 'r', BEFORE, HEAD]]);
+});
+
+test('new-branch push (before = zero sha) falls back to head commit diff', async () => {
+  const g = giteaStub();
+  const out = await fetchDiff({
+    gitea: g,
+    job: { owner: 'o', repo: 'r', prIndex: null, sha: HEAD, before: '0'.repeat(40), commitShas: [HEAD] }
+  });
+  assert.equal(out, 'HEADDIFF');
+  assert.deepEqual(g.calls, [['commit', 'o', 'r', HEAD]]);
+});
+
+test('missing before also falls back to head commit diff', async () => {
+  const g = giteaStub();
+  const out = await fetchDiff({
+    gitea: g,
+    job: { owner: 'o', repo: 'r', prIndex: null, sha: HEAD, before: null, commitShas: [HEAD] }
+  });
+  assert.equal(out, 'HEADDIFF');
+  assert.deepEqual(g.calls, [['commit', 'o', 'r', HEAD]]);
+});
+
+test('compare failure propagates (no silent placeholder diff)', async () => {
+  const g = giteaStub();
+  g.getCompareDiff = () => Promise.reject(new Error('boom 500'));
+  await assert.rejects(
+    () => fetchDiff({ gitea: g, job: { owner: 'o', repo: 'r', prIndex: null, sha: HEAD, before: BEFORE } }),
+    /boom 500/
+  );
+});