perf(resolution): batch-loop de-quadratic — keyset reads, changes-based guard, DB-scaled valve caps + resolve profiler (#1339)

The §7a.2 per-ref profile overturned the assumption the whole arc was
built on: resolveOne owns only ~93s of the kernel-scale ~433s batch loop.
Loop-stage attribution (CODEGRAPH_RESOLVE_PROFILE, shipped here) named the
rest: backpressure folds 111.2s, count guard 93.9s, batch reads 54.6s,
deletes/inserts/marks ~84s, settle 85.7s.

- Non-progress guard O(remaining)→O(1): the per-batch COUNT(*) walked every
  remaining pending row (O(N²/batch) per run, 93.9s). The cleanup queries
  now return summed SQLite , and zero-removals-from-claimed-work
  is the guard signal — the DIRECT evidence the count diff inferred (a
  mismatched-name resolver makes keyed cleanup no-op ⇒ changes=0). A real
  COUNT runs only on that suspicious path and arbitrates exactly as before.
- Batch reads OFFSET→keyset (54.6s→O(batch)): OFFSET re-walked the
  accumulated failed-row prefix every read; seeking past the last-seen
  rowid is prefix-independent and enumeration-order identical.
- WAL valve caps scale with DB size (env still wins): every fold re-writes
  hot pages (#1231 in bounded form — 111.2s at the flat 256MB cap);
  soft=clamp(dbSize/4, 256MB, 2GB) trades ~4× fewer folds for a transient
  WAL ≈ project size.
- CODEGRAPH_RESOLVE_PROFILE: per-outcome resolveOne histogram + loop-stage
  attribution, main + workers, off by default.

Gates: dubbo dump byte-identical; suite 2,491 passed / 4 skipped (kernel
required). Kernel-scale payoff run lands in the plan doc next.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

__tests__/wal-deferral.test.ts

@@ -416,3 +416,14 @@ describe('valve file-size trigger (§7a.1: backfilled WAL still grows the file)'
     db.close();
   });
 });
+
+describe('resolveWalValveMb DB-size scaling (§7a.2 fold-tax reduction)', () => {
+  it('scales soft cap ~dbSize/4 within [256, 2048]MB; env always wins', () => {
+    const GB = 1024 * 1024 * 1024;
+    expect(resolveWalValveMb(undefined, 100 * 1024 * 1024)).toBe(256); // floor
+    expect(resolveWalValveMb(undefined, 4.6 * GB)).toBe(1177); // ~dbSize/4
+    expect(resolveWalValveMb(undefined, 40 * GB)).toBe(2048); // ceiling
+    expect(resolveWalValveMb('64', 40 * GB)).toBe(64); // env override wins
+    expect(resolveWalValveMb(undefined, 0)).toBe(256); // unknown size → default
+  });
+});