feat(confidence-engine): synthesize not relevant findings

docs/current-handoff.md

@@ -2920,6 +2920,44 @@ The synthesis route now supplies the configured `OLLAMA_MODEL` and the domain re
 - Current Understanding visibly replaced (reconstruction incorporates corrected Finding)
 - Same Finding remains at same position, disposition returns to normal state
 
+### THIRD synthesis trigger integrated (v0.50.3 — Not Relevant disposition)
+
+- `components/scenario-form.jsx` — `updateFindingDisposition` now triggers `synthesizeFromFindings` when disposition transitions TO `not_relevant`
+- Same explicit-next-state pattern: construct `nextFindings` from local `findings` → call `setFindings(() => nextFindings)` → gate synthesis on `newDisposition === "not_relevant"`
+
+**Changes:**
+- `updateFindingDisposition` (line 267): derives `nextFindings` explicitly from local args → calls `setFindings(() => nextFindings)` → if newDisposition is `"not_relevant"`, calls `synthesizeFromFindings(fetch, { situationGraph: currentGraph, findings: normalizeFindings(nextFindings) })` → replaces CU on success; no fallback/approach on failure
+
+**Deterministic gate:**
+- Not Relevant trigger tests (Cases 1–6): 6/6 PASS
+- Finding trigger tests total: 30/30 PASS (original 24 + correction 5 + not_relevant 6 — 1 was "restore = no synthesis")
+- focused-Finding regression: 19/19 PASS
+- synthesis seam + route: 54/54 PASS
+- build: PASS
+
+**Trigger contract:**
+- Not Relevant click on eligible Finding → 1 synthesis call ✅
+- Complete canonical Findings array sent (including the now-not_relevant Finding) ✅
+- Eligibility filtering owned by synthesis domain (no pre-filter in ScenarioForm) ✅
+- Finding.id preserved ✅
+- proposition preserved ✅
+- sourceObservation preserved ✅
+- contributionId preserved ✅
+- Other Findings unchanged in payload ✅
+- Previous CU NOT sent as synthesis input ✅
+- not_relevant state preserved on synthesis failure ✅
+- Previous CU preserved on synthesis failure ✅
+- No automatic retry ✅
+- No legacy append fallback ✅
+- Restore (not_relevant → null) → 0 synthesis calls for this increment ✅
+
+**Live runtime (classification RUN-C):**
+- One eligible Finding → clicked "not relevant"
+- Exactly 1 `/api/cases/synthesis` → HTTP 200
+- Finding visibly became Not Relevant (button toggled from "not relevant" to "restore")
+- Current Understanding visibly replaced with new reconstruction text
+- Same Finding remains at same position, disposition shows as "Not Relevant"
+
 ### NEXT BOUNDED ISSUE (for future reference)
 
 #### Name