chore(#597): replace count-based ratchet guards with AST lint + named-set allowlists (#603)

The windows-test-parity ratchet greps test source for fs.rmSync-without-
maxRetries (and six other Windows-portability anti-patterns), failing when an
integer offender COUNT exceeds a frozen baseline (rmSync: 95). A count ratchet
is a Goodhart metric: fixing one offender and adding another keeps the count
constant, so a new defect slips through green. Replace it — and every other
count ratchet in the repo — with a layered, masking-proof design.

Behavioral seam test
- tests/helpers-cleanup.test.cjs proves helpers.cleanup() carries the Windows
  EBUSY retry budget. cleanup() delegates retries to Node's fs.rmSync via
  maxRetries (it owns no loop), so the test asserts the option contract
  (recursive/force/maxRetries>0/retryDelay>0) + real-FS removal + the cwd-guard,
  rather than a loop that does not exist. The EBUSY risk is now tested ONCE at
  the helper, not approximated textually at every call site.

Write-time ESLint rule (AST-accurate, replaces the grep)
- eslint-rules/no-raw-rmsync-in-tests.cjs (error in tests/**/*.test.cjs) bans
  raw fs.rmSync, steering to cleanup(). Catches member, computed (fs['rmSync']),
  destructured and aliased forms; escape hatch is inline
  `// eslint-disable-next-line local/no-raw-rmsync-in-tests -- <reason>` only.
- Migrated 336 raw fs.rmSync teardown calls across ~116 test files to cleanup().
  ~18 genuinely load-bearing sites (mid-test SUT/fault-injection removals,
  error-swallowing or name-colliding local teardown helpers) keep the raw call
  with an inline eslint-disable + reason.

Shared anti-ratchet primitive
- scripts/lib/allowlist-ratchet.cjs:
  - assertWithinAllowlist: fails on NOVEL ids (new offender introduced) AND on
    STALE ids (a known offender was fixed but not pruned) — identity, not count,
    and a ratchet DOWN toward zero.
  - assertTightCeiling: a size/length budget whose ceiling must stay within a
    grace band of the high-water mark, so budgets may only tighten, never creep.

Ratchets converted onto the primitive
- windows-test-parity-guard.test.cjs: rmSync rule deleted (now ESLint-enforced);
  the remaining six patterns moved from integer baselines to named-set
  allowlists with ratchet-down.
- scripts/lint-test-file-count.{cjs,allowlist.json}: per-module integer counts →
  named filename sets (closes the swap-a-file-keep-the-count blind spot); a
  module dropping under cap now FAILS to force pruning its allowlist entry.
- enh-2790 skill-count `<= 63` → named skill allowlist (ratchets toward ~58).

Size budgets hardened (tighten-only)
- agent-size / workflow-size / feat-3039 help-tiered: ceilings lowered to the
  current high-water mark and an assertTightCeiling anti-creep check added per
  tier. Fixed external-contract limits (description ≤100 chars, agent ≤100 KB)
  are intentionally left as-is — they are not grandfathered creeping budgets.

No user-facing behavior change (tests + tooling only); no USER_FACING_PREFIXES
touched, so no changeset fragment is required.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

tests/runtime-artifact-layout-surface.test.cjs

@@ -323,7 +323,7 @@ describe('resolveSurface', () => {
         'surface with no state should equal profile resolution'
       );
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 
@@ -351,7 +351,7 @@ describe('resolveSurface', () => {
         }
       }
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 
@@ -376,7 +376,7 @@ describe('resolveSurface', () => {
         assert.ok(resolved.skills.has(dep), `transitive dep "${dep}" of sketch must be present`);
       }
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 
@@ -395,7 +395,7 @@ describe('resolveSurface', () => {
 
       assert.ok(!resolved.skills.has('progress'), '"progress" must be removed by explicitRemoves');
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 
@@ -410,7 +410,7 @@ describe('resolveSurface', () => {
       assert.ok(typeof resolved.name === 'string');
       assert.ok(resolved.agents instanceof Set);
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 
@@ -434,7 +434,7 @@ describe('resolveSurface', () => {
         'surface baseProfile takes precedence over marker'
       );
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 
@@ -463,7 +463,7 @@ describe('resolveSurface', () => {
         }
       }
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 });
@@ -484,7 +484,7 @@ describe('readSurface / writeSurface', () => {
       const read = readSurface(dir);
       assert.deepStrictEqual(read, state);
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 
@@ -500,7 +500,7 @@ describe('readSurface / writeSurface', () => {
       writeSurface(dir, state);
       assert.deepStrictEqual(readSurface(dir), state);
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 
@@ -516,7 +516,7 @@ describe('readSurface / writeSurface', () => {
       writeSurface(dir, state);
       assert.deepStrictEqual(readSurface(dir), state);
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 
@@ -526,7 +526,7 @@ describe('readSurface / writeSurface', () => {
       const result = readSurface(dir);
       assert.strictEqual(result, null);
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 
@@ -543,7 +543,7 @@ describe('readSurface / writeSurface', () => {
       const result = readSurface(dir);
       assert.strictEqual(result, null);
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 
@@ -558,7 +558,7 @@ describe('readSurface / writeSurface', () => {
       const result = readSurface(dir);
       assert.strictEqual(result, null);
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 
@@ -573,7 +573,7 @@ describe('readSurface / writeSurface', () => {
       const result = readSurface(dir);
       assert.strictEqual(result, null);
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 
@@ -587,7 +587,7 @@ describe('readSurface / writeSurface', () => {
       assert.deepStrictEqual(tmpFiles, [], 'no tmp files should remain after write');
       assert.ok(files.includes('.gsd-surface.json'));
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 
@@ -600,7 +600,7 @@ describe('readSurface / writeSurface', () => {
       assert.strictEqual(read.baseProfile, 'standard');
       assert.deepStrictEqual(read.disabledClusters, ['utility']);
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 
@@ -612,7 +612,7 @@ describe('readSurface / writeSurface', () => {
       assert.ok(fs.existsSync(nested));
       assert.ok(readSurface(nested) !== null);
     } finally {
-      fs.rmSync(base, { recursive: true, force: true });
+      cleanup(base);
     }
   });
 });
@@ -720,7 +720,7 @@ describe('listSurface', () => {
       assert.ok(Array.isArray(result.disabled), 'disabled must be array');
       assert.ok(typeof result.tokenCost === 'number', 'tokenCost must be number');
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 
@@ -737,7 +737,7 @@ describe('listSurface', () => {
       assert.ok(typeof result.tokenCost === 'number', 'tokenCost must be number');
       assert.ok(result.tokenCost >= 0, 'tokenCost must be non-negative');
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 
@@ -758,7 +758,7 @@ describe('listSurface', () => {
       assert.ok(coreList.enabled.length + coreList.disabled.length === totalStems,
         'enabled + disabled must equal total stems');
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 
@@ -784,7 +784,7 @@ describe('listSurface', () => {
       assert.ok(afterList.tokenCost <= beforeList.tokenCost,
         'disabling a cluster should not increase token cost');
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 
@@ -807,7 +807,7 @@ describe('listSurface', () => {
 
       assert.strictEqual(result.tokenCost, expected, 'tokenCost must equal sum of description lengths ÷ 4');
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 
@@ -822,7 +822,7 @@ describe('listSurface', () => {
       assert.deepStrictEqual(result.enabled, [...result.enabled].sort());
       assert.deepStrictEqual(result.disabled, [...result.disabled].sort());
     } finally {
-      fs.rmSync(dir, { recursive: true, force: true });
+      cleanup(dir);
     }
   });
 });