test(coverage): close 5 remaining v1.46.0.0 test gaps (A-E)

Five behaviors that v1.46 ships but had no test coverage. All now pinned.

A) --host all idempotency (test/gen-skill-docs-idempotency.test.ts)
   The default test ran Claude host only. Non-Claude hosts (Codex, Factory,
   Cursor, OpenClaw, GBrain, Slate, OpenCode, Hermes, Kiro) each have their
   own output paths and could carry their own non-deterministic fields. We
   hit a "--host all needed for freshness check" mid-/ship. Now: two
   consecutive `bun run gen:skill-docs --host all` runs must produce
   byte-identical outputs across a per-host sample (.agents/, .cursor/,
   .factory/, .gbrain/). Catches per-host adapter regressions before CI.

B) --catalog-mode=full opt-out (test/catalog-mode-full.test.ts)
   The legacy escape hatch had zero tests. 6 new tests across two layers:
   static (CATALOG_MODE_ARG parsed; conditional gate present; default is
   "trim"; invalid value throws) + smoke (actual --catalog-mode=full run
   produces a multi-line `description: |` block + omits "## When to invoke"
   body section; mutates the working tree then restores in a finally block).

C) parity-baseline-v1.44.1.json integrity (test/parity-baseline-integrity.test.ts)
   The baseline is the source of every v1→v2 number cited in the
   CHANGELOG v1.46.0.0 entry. Anyone could edit it without test failure
   until now. 8 new tests pin: existence, tag, capturedFromCommit
   allowlist, expected v1.44 numbers (51 skills, ~2,915 KB, ~9,319
   catalog tokens), CHANGELOG references this file by path, per-skill
   shape, and a SHA256 byte-stability hash. Any edit fails with a clear
   "if intentional, update EXPECTED_HASH AND the CHANGELOG numbers" signal.

D) Live appliesTo gate end-to-end (test/resolver-entry.test.ts extended)
   The unwrapResolver unit tests covered the function; the gen-skill-docs.ts
   substitution loop that USES the gate had no integration coverage. 6 new
   tests simulate the exact 4-line shape from gen-skill-docs.ts:457-467
   against synthetic registries: plain-function fires unconditionally,
   gated fires when true / empty-string when false, mixed registries
   compose, parameterized resolvers respect gates, unknown resolvers throw.

E) Per-skill min-size floor (test/skill-size-budget.test.ts extended)
   The existing 200-byte body coverage-floor is a noise floor — a skill
   that lost 99.75% of content still passes. 1 new test asserts every
   skill stays ≥80% of its v1.44.1 baseline size (the parity-suite
   content invariants only covered 10 of 51 skills; the remaining 41
   were uncovered). SECTIONS_EXTRACTED hook in place for v2.0.0.0 when
   the sections/ pattern legitimately shrinks ship/plan-ceo/etc. past
   the floor.

Test plan:
- bun test focused 17-file suite: 1202 pass, 0 fail
  (+23 new tests vs the pre-fill 1179 baseline)
- catalog-mode=full mutates working tree then restores cleanly
- --host all idempotency runs two full gen passes in <1s on this machine

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

test/skill-size-budget.test.ts

@@ -126,6 +126,75 @@ describe('SKILL.md size budget regression (gate, free)', () => {
     );
   });
 
+  /**
+   * Gap E (v1.46.0.0): per-skill min-size floor.
+   *
+   * The existing skill-coverage-floor enforces body ≥ 200 bytes, which is
+   * a tiny noise floor. A skill that was 100 KB at v1.44.1 and shrinks to
+   * 250 bytes passes that check despite losing 99.75% of content. The
+   * parity-suite content invariants cover this for 10 hand-picked skills
+   * (cso, ship, plan-ceo, etc.); the remaining 41 skills had no per-skill
+   * shrinkage floor.
+   *
+   * Floor: 80% of the v1.44.1 baseline. v1.46 actual shrinkage is <1% per
+   * skill, so this is a comfortable ceiling that still catches accidental
+   * mass deletion (e.g., a refactor that strips the body of a skill).
+   *
+   * v2.0.0.0 will introduce the sections/ pattern for 5 heavyweights
+   * (ship, plan-ceo-review, office-hours, plan-eng-review,
+   * plan-design-review). Those skills will legitimately shrink to ~15 KB
+   * skeletons. When that lands, add them to SECTIONS_EXTRACTED so the floor
+   * relaxes for them.
+   */
+  test('no skill shrinks past 80% of v1.44.1 baseline (catches accidental body strip)', () => {
+    const baseline: ParityBaseline = JSON.parse(fs.readFileSync(BASELINE_PATH, 'utf-8'));
+    const current = captureBaseline({ repoRoot: REPO_ROOT });
+    const MIN_RATIO = 0.80; // a skill at <80% of its v1.44 size signals mass-deletion
+    const SECTIONS_EXTRACTED = new Set<string>(); // populate in v2.0.0.0 when sections/ lands
+
+    const undershoots: Array<{
+      skill: string; beforeBytes: number; afterBytes: number; ratio: number;
+    }> = [];
+    for (const [skill, before] of Object.entries(baseline.skills)) {
+      if (SECTIONS_EXTRACTED.has(skill)) continue;
+      const after = current.skills[skill];
+      if (!after) continue; // skill removed since baseline — separate concern
+      const ratio = after.skillMdBytes / before.skillMdBytes;
+      if (ratio < MIN_RATIO) {
+        undershoots.push({
+          skill, beforeBytes: before.skillMdBytes, afterBytes: after.skillMdBytes, ratio,
+        });
+      }
+    }
+
+    if (undershoots.length === 0) return;
+
+    const overrideReason = process.env.GSTACK_SIZE_BUDGET_OVERRIDE_REASON?.trim();
+    if (overrideReason) {
+      logBudgetOverride({
+        scope: 'skill-size-budget-floor',
+        reason: overrideReason,
+        details: { min_ratio: MIN_RATIO, undershoots },
+      });
+      // eslint-disable-next-line no-console
+      console.warn(
+        `[skill-size-budget-floor] OVERRIDE APPLIED (${overrideReason}) — ${undershoots.length} undershoot(s) allowed`,
+      );
+      return;
+    }
+
+    const msg = undershoots.map(u =>
+      `  ${u.skill}: ${u.beforeBytes} → ${u.afterBytes} bytes (×${u.ratio.toFixed(2)} — below ${MIN_RATIO} floor)`,
+    ).join('\n');
+    throw new Error(
+      `${undershoots.length} skill(s) shrunk past v1.44.1 × ${MIN_RATIO} floor:\n${msg}\n` +
+      `This usually signals accidental body strip (e.g., a resolver returning empty, a ` +
+      `template losing a section). If the shrinkage is intentional (e.g., the skill moved ` +
+      `to the sections/ pattern), add it to SECTIONS_EXTRACTED in this test. Override: ` +
+      `GSTACK_SIZE_BUDGET_OVERRIDE_REASON="why" allows + audit-logs.`,
+    );
+  });
+
   test('catalog token estimate stays compressed (v1.45 target ≤ 7000)', () => {
     const current = captureBaseline({ repoRoot: REPO_ROOT });
     const v145Target = 7000;