fix(continual-learning): harden wasRealCollision verifier (Codex review)

Addresses the P1 brittleness in the Step 3 verifier so learned_from edges
(graph/live.ts:413) can't be silently zeroed on stage.

- Capture overlap AT detection time as Collision.gitOverlap (podman.ts), while
  engineer_states are still fresh, instead of re-deriving from possibly-stale
  state when the user clicks. deriveWasRealCollision() now prefers this stored
  evidence and only falls back to a live re-derivation for older collisions.
- Canonicalize engineer names (trim + lowercase) on both the capture and the
  fallback path, so "Karti" vs "karti" no longer misses the git state.
- conflictKey now reuses the shared comparableBasename() helper (dedupe).

shared/src/collision.ts gains optional `gitOverlap?: boolean` (additive).
shared rebuilt; backend+frontend typecheck + eslint pass. PLAN.md rung 3 updated.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/src/agent/podman.ts

@@ -9,11 +9,42 @@ import {
   recordIntervention,
   updateInterventionStatus,
 } from '../memory/store.js';
-import { getGitStates } from '../memory/db.js';
+import { getGitStates, type GitState } from '../memory/db.js';
 import { recallSimilar } from '../memory/vectors.js';
 import { shouldIntervene, preferredAction } from '../memory/policy.js';
 import { publishHermesIntervention } from '../action/hermes.js';
 
+/** Strip a git-status prefix ("M ", "?? ") and reduce a path to its lowercased
+ *  basename — matches comparableFile() in memory/store.ts so keys line up. */
+function comparableBasename(raw?: string): string {
+  return (
+    (raw ?? '')
+      .trim()
+      .replace(/^(\?\?|[MADRCU!]{1,2})\s+/, '')
+      .split(/[\\/]/)
+      .pop()
+      ?.toLowerCase() ?? ''
+  );
+}
+
+/** Canonicalize an engineer name for case/whitespace-insensitive matching, so
+ *  "Karti" and "karti" resolve to the same engineer's git state. */
+function canonicalName(raw?: string): string {
+  return (raw ?? '').trim().toLowerCase();
+}
+
+/** Git ground truth: do ALL involved engineers currently have the collided file
+ *  in their changedFiles? Computed at detection time while git state is fresh. */
+function engineersOverlapOnFile(collision: Collision, gitStates: Map<string, GitState>): boolean {
+  const target = comparableBasename(collision.file);
+  if (!target || collision.engineers.length < 2) return false;
+  const byCanon = new Map<string, string[]>();
+  for (const [name, st] of gitStates) byCanon.set(canonicalName(name), st.changedFiles);
+  return collision.engineers.every((e) =>
+    (byCanon.get(canonicalName(e)) ?? []).some((f) => comparableBasename(f) === target),
+  );
+}
+
 export class PodMan {
   private contexts = new Map<string, EngineerContext>();
   /**
@@ -75,6 +106,12 @@ export class PodMan {
       if (!current.has(key)) this.activeConflicts.delete(key);
     }
 
+    // Capture git ground-truth overlap now, while engineer_states are fresh, so
+    // the outcome-time verifier never depends on a stale sidecar or a late click.
+    for (const collision of collisions) {
+      collision.gitOverlap = engineersOverlapOnFile(collision, gitStates);
+    }
+
     for (const collision of collisions) await this.handle(collision);
   }
 
@@ -85,14 +122,7 @@ export class PodMan {
    * basename.
    */
   private conflictKey(collision: Collision): string {
-    return (
-      (collision.file ?? '')
-        .trim()
-        .replace(/^(\?\?|[MADRCU!]{1,2})\s+/, '')
-        .split(/[\\/]/)
-        .pop()
-        ?.toLowerCase() ?? ''
-    );
+    return comparableBasename(collision.file);
   }
 
   private async handle(collision: Collision): Promise<void> {

backend/src/memory/store.ts

@@ -96,15 +96,22 @@ export async function deriveWasRealCollision(outcome: InterventionOutcome): Prom
   try {
     const c = await collections();
     const collision = await c.collisions.findOne({ id: outcome.collisionId });
-    if (!collision || !Array.isArray(collision.engineers) || collision.engineers.length < 2) {
-      return false;
-    }
+    if (!collision) return false;
+    // Prefer the overlap evidence captured at detection time (fresh git state):
+    // immune to late clicks, stale sidecars, and the engineer_states TTL.
+    if (typeof collision.gitOverlap === 'boolean') return collision.gitOverlap;
+    // Fallback for collisions detected before gitOverlap was captured: re-derive
+    // from latest git state, matching engineers on case/whitespace-canonical names.
+    if (!Array.isArray(collision.engineers) || collision.engineers.length < 2) return false;
     const target = comparableFile(collision.file);
     if (!target) return false;
-    const gitStates = await getGitStates(outcome.podId);
-    const touchesTarget = (name: string): boolean =>
-      (gitStates.get(name)?.changedFiles ?? []).some((f) => comparableFile(f) === target);
-    return collision.engineers.every(touchesTarget);
+    const byCanon = new Map<string, string[]>();
+    for (const [name, st] of await getGitStates(outcome.podId)) {
+      byCanon.set(name.trim().toLowerCase(), st.changedFiles);
+    }
+    return collision.engineers.every((e) =>
+      (byCanon.get(e.trim().toLowerCase()) ?? []).some((f) => comparableFile(f) === target),
+    );
   } catch (err) {
     console.error(`[memory] wasRealCollision verifier failed: ${(err as Error).message}`);
     return false;

docs/PLAN.md

@@ -510,14 +510,19 @@ no schema change. Owner: RSI track. Independent of the MongoDB-cleanup handoff.
      kind), `plan.md:66` (second similar event behaves differently).
 
 3. **Step 3 - derive `wasRealCollision` from git overlap (backend-authoritative)** ✅
-   - `backend/src/memory/store.ts` `recordOutcome` now overrides the
-     client-supplied `wasRealCollision` with `deriveWasRealCollision()`: a
-     collision is real only if BOTH named engineers currently have the collided
-     file in their git `changedFiles` (`getGitStates`, 120s freshness TTL).
-     Conservative `false` when orphaned/stale. `frontend/.../useInterventions.ts`
-     stops sending a hardcoded `true` (now a backend-overridden placeholder).
-   - Restores the (accepted × wasReal) 2×2 the spec assumes.
+   - Overlap is captured AT detection time as `Collision.gitOverlap`
+     (`backend/src/agent/podman.ts`), while `engineer_states` are still fresh —
+     true only if ALL involved engineers have the collided file in their git
+     `changedFiles`, matched on case/whitespace-canonical names.
+   - `backend/src/memory/store.ts` `recordOutcome` overrides the client value
+     with `deriveWasRealCollision()`, which prefers the stored `gitOverlap`
+     (immune to late clicks / stale sidecars / the 120s TTL) and only falls back
+     to a live canonical-name re-derivation for pre-existing collisions.
+     `frontend/.../useInterventions.ts` stops sending hardcoded `true`.
+   - Restores the (accepted × wasReal) 2×2 the spec assumes; keeps `learned_from`
+     edges (`graph/live.ts:413`) from being silently zeroed on stage.
    - Spec: `docs/continual-learning/spec.md:98-108`, `policy.md:35-42`.
+   - Hardened per Codex review (name canonicalization + detection-time capture).
 
 Follow-ups (separate rungs, not in this change): Step 4-5 `strategy_versions` +
 Gemini-proposed `LearningProposal` slice; Step 6 durable `owns` write; seed a

shared/src/collision.ts

@@ -16,6 +16,14 @@ export interface Collision {
   severity: CollisionSeverity;
   /** Snapshot of relevant GitHub state at detection time. */
   githubState?: GithubStateSnapshot;
+  /**
+   * Git ground-truth overlap captured AT detection time, while engineer_states
+   * are still fresh: true when every involved engineer had `file` in their git
+   * changedFiles. Read as the authoritative wasRealCollision evidence at outcome
+   * time, so a late click, a stale sidecar, or the engineer_states freshness TTL
+   * cannot retroactively zero it out.
+   */
+  gitOverlap?: boolean;
   detectedAt: string;
 }