fix(verdict): findings resolved by the change under review never block

The review model routinely narrates the pre-existing bug a PR fixes as a
critical/confirmed correctness finding; deriveVerdict then failed the very
change that fixes it (three consecutive A-grade reviews of shreai#188
verdicted fail this way). Findings now carry resolved_by_this_change
(prompted, schema'd, normalized); resolved findings are excluded from
fail/warn derivation, and a model-level warn whose findings are all
resolved normalizes to pass. Introduced-or-remaining defects still block.

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01AD1cPDz563Fyppc7T4ibhU

src/lib/prompt.js

@@ -19,12 +19,14 @@ Output schema (every key required):
   "findings": [
     {"title": "...", "file": "path", "line": 123, "severity": "critical"|"high"|"medium"|"low",
      "confidence": "confirmed"|"plausible", "axis": "correctness"|"security"|"tests_coverage"|"design_simplicity"|"performance"|"style"|"breaking_changes"|"docs",
+     "resolved_by_this_change": true|false,
      "detail": "what is wrong, concrete failure scenario, and the fix"}
   ],
   "verdict": "pass"|"warn"|"fail"
 }
 
 Rules:
+- A finding must describe a defect that EXISTS IN THE RESULTING CODE after this diff is applied. The pre-existing bug that this diff FIXES is not a finding — acknowledge it in the correctness rationale instead. If you still list it (e.g. for the record), you MUST set "resolved_by_this_change": true on that finding; findings the diff introduces or leaves unfixed get "resolved_by_this_change": false.
 - "confirmed" means you can trace a concrete failure from the diff alone; anything needing unseen context is "plausible".
 - severity critical/high is reserved for real correctness bugs, security holes, data loss, or breaking API changes.
 - verdict "fail" ONLY when a confirmed critical/high correctness or security finding exists; "warn" for notable but non-blocking issues; otherwise "pass".

src/lib/verdict.js

@@ -7,6 +7,10 @@ const BLOCKING_AXES = new Set(['correctness', 'security']);
 
 export function isBlockingFinding(f) {
   if (!f || typeof f !== 'object') return false;
+  // A finding the diff itself resolves describes the PRE-change state; it
+  // cannot block the change that fixes it (models routinely narrate the fixed
+  // bug as a critical/confirmed finding, which failed correct fixes).
+  if (f.resolved_by_this_change === true) return false;
   const sev = String(f.severity || '').toLowerCase();
   const conf = String(f.confidence || '').toLowerCase();
   if (!BLOCKING_SEVERITIES.has(sev)) return false;
@@ -21,12 +25,16 @@ export function deriveVerdict(review) {
   const findings = Array.isArray(review?.findings) ? review.findings : [];
   if (findings.some(isBlockingFinding)) return 'fail';
   const hasWarn = findings.some(f => {
+    if (f?.resolved_by_this_change === true) return false;
     const sev = String(f?.severity || '').toLowerCase();
     return sev === 'critical' || sev === 'high' || sev === 'medium';
   });
   if (hasWarn) return 'warn';
-  // trust the model's verdict if it said warn without matching findings
-  if (review?.verdict === 'warn') return 'warn';
+  // Trust the model's verdict if it said warn without matching findings —
+  // unless every finding it gave is resolved_by_this_change, in which case its
+  // warn is about the pre-change state and the resulting code is clean.
+  const allResolved = findings.length > 0 && findings.every(f => f?.resolved_by_this_change === true);
+  if (review?.verdict === 'warn' && !allResolved) return 'warn';
   return 'pass';
 }
 
@@ -49,6 +57,7 @@ export function normalizeReview(raw) {
     severity: pick(String(f?.severity || '').toLowerCase(), ['critical', 'high', 'medium', 'low'], 'low'),
     confidence: pick(String(f?.confidence || '').toLowerCase(), ['confirmed', 'plausible'], 'plausible'),
     axis: f?.axis ? String(f.axis).toLowerCase() : null,
+    resolved_by_this_change: f?.resolved_by_this_change === true,
     detail: String(f?.detail ?? '').slice(0, 2000)
   }));
   const review = {