fix(pty-runner): positional floor exclusion, flag builder, outcome union, token tracking

Review-army + adversarial findings on the scope-gate observability work,
all verified before fixing:

- Floor check: acceptance scanned the CUMULATIVE buffer while the scope-gate
  exclusion scanned only the 1500-byte tail, so an early gate render satisfied
  the floor vacuously once ~1.5KB of output accumulated (found independently
  by 4 review passes; predicate reproduced). Acceptance now scans only content
  APPENDED after the first gate render (positional anchor), and the LLM-judge
  'waiting' shortcut no longer fires while the gate menu is the pending render.
- High-water flags are built once and spread at every return path — the
  hand-spread pattern had already drifted (judge-waiting return omitted two
  flags), which made must-stay-false asserts vacuous on those paths.
- isScopeGateAutoSelectVisible: tense-tolerant selected/selecting/selects
  token (must-be-TRUE asserts shouldn't fail semantically-perfect paraphrases)
  and quoted-occurrence rejection (a model verbatim-quoting the announcement
  while declining must not trip must-stay-FALSE asserts). Fixtures added for
  both directions.
- PlanSkillObservation outcome union gains 'wrote_findings_before_asking'
  (returned at runtime via classifyVisible but missing from the type).
- trackTokens/tokensObserved: cumulative-buffer token high-water for
  consumption asserts (the 2KB evidence tail is lossy and the plan-file
  fallback is unreachable outside plan mode).
- New scope-gate-floor unit pins (from the ship coverage audit): both gate
  render forms trip acceptance and exclusion; a genuine finding AUQ is not
  excluded; tail-scoping semantics pinned.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

test/helpers/claude-pty-runner.unit.test.ts

@@ -264,6 +264,33 @@ Recommendation: A when a branch diff exists, otherwise B.
       expect(isScopeGateAutoSelectVisible(sample)).toBe(false);
     });
 
+    test('stays false on a VERBATIM QUOTE of the announcement (negation narration)', () => {
+      // The exact announcement line sits quoted in the skill context, so a
+      // model explaining why it is NOT firing it can reproduce it byte-exact
+      // inside quotes — that must not trip a must-stay-false assert.
+      const sample =
+        'Not in plan mode, so I won\'t announce "Scope gate: plan mode — auto-selected B (reviewing <target>)." and will ask instead.';
+      expect(isScopeGateAutoSelectVisible(sample)).toBe(false);
+    });
+
+    test('a later real render still matches after an earlier quoted mention', () => {
+      const sample =
+        'Earlier I said I would render "Scope gate: plan mode — auto-selected B (…)" and now:\n' +
+        'Scope gate: plan mode — auto-selected B (reviewing PLAN.md).';
+      expect(isScopeGateAutoSelectVisible(sample)).toBe(true);
+    });
+
+    test('matches tense paraphrases WITH the announcement prefix (auto-selecting / auto-selects)', () => {
+      expect(
+        isScopeGateAutoSelectVisible('Scope gate: plan mode — auto-selecting B (reviewing the drafted plan).'),
+      ).toBe(true);
+      expect(isScopeGateAutoSelectVisible('Scope gate: plan mode — auto-selects B.')).toBe(true);
+    });
+
+    test('stays false on tense paraphrases WITHOUT the announcement prefix', () => {
+      expect(isScopeGateAutoSelectVisible('Auto-selecting B since we are in plan mode.')).toBe(false);
+    });
+
     test('stays false on AUTO_DECIDE preamble output', () => {
       const sample = 'Auto-decided scope question → B (your preference). Change with /plan-tune.';
       expect(isScopeGateAutoSelectVisible(sample)).toBe(false);