fix(coding): keep optimistic identity across snapshots

.project-docs/30-worklog/tasks/20260823-pi-renderer-store-b7e2c4a1.md

@@ -107,7 +107,10 @@
   and replayed in generation/sequence order after a valid Snapshot; unresolved
   pending/accepted/uncertain prompt requests re-overlay their local optimistic
   nodes after snapshot-first reconnect until a durable `clientRequestId`
-  reconciliation arrives. Neither mechanism replays a mutation.
+  reconciliation arrives. If the reconnect Snapshot already contains that
+  durable message, its message id is first reconciled to the local request's
+  stable UI node id before the request is removed. Neither mechanism replays a
+  mutation.
 - Added optimistic user nodes keyed by `clientRequestId`. Durable upsert keeps
   the optimistic UI node id; definite rejection restores an untouched draft
   and marks the node failed; uncertain delivery restores the draft while
@@ -129,11 +132,16 @@
 
 - `pnpm exec vitest run tests/unit/coding-conversations-facade.test.ts tests/unit/coding-conversations-store.test.tsx`:
   initial implementation 2 files / 12 tests passed; after review fixes, 2 files
-  / 13 tests passed, including delayed gap GET + concurrent patch replay and
+  / 14 tests passed, including delayed gap GET + concurrent patch replay,
-  reconnect Snapshot optimistic-node continuity.
+  reconnect Snapshot optimistic-node continuity, and a reconnect Snapshot that
+  already contains the durable user message while preserving `node-1`.
 - `pnpm exec vitest run` for the two PI-110 tests plus PI-010 contracts,
   coding core routes, event projector, Conversation runtime, product tools,
-  and subagent suites: 8 files / 75 tests passed.
+  and subagent suites: initial 8 files / 75 tests; final review-fix range 8
+  files / 77 tests passed. One intervening parallel run hit a non-reproducible
+  `CODING_STORAGE_WRITE_FAILED` in the unrelated Conversation runtime temp
+  persistence test; that file passed alone immediately afterward and the same
+  8-file command then passed in full.
 - `pnpm run typecheck`: passed after the shared product seam removed the clean
   Renderer -> composite Electron declaration dependency.
 - `pnpm run lint:check`: passed with zero errors and the same six unrelated
@@ -150,9 +158,12 @@
   PI-150. Neither is recorded as Pass.
 - Planner review of `a072257...36626c8`: Standards PASS / 0 findings; Spec
   Needs Fix with two P1 findings for recovery-window patch loss and reconnect
-  Snapshot optimistic-node loss. Both independent reproductions were accepted
+  Snapshot optimistic-node loss. The first fixed-range re-review accepted gap
-  and fixed locally with the focused regressions above; fixed-range re-review
+  replay and missing-durable-node overlay, then found one remaining P1 where a
-  remains required before PI-110 can be marked Done.
+  Snapshot already containing the durable node adopted the server id. That
+  reproduction is now fixed by `clientRequestId` id reconciliation before
+  request cleanup, with the focused regression above. Final fixed-range
+  re-review remains required before PI-110 can be marked Done.
 
 ## Follow-ups
 

src/stores/coding-conversations.ts

@@ -160,6 +160,22 @@ function withoutReconciledRequests(
   );
 }
 
+function withReconciledOptimisticNodeIds(
+  snapshot: ConversationSnapshot,
+  requests: Record<string, CodingPromptRequestState> | undefined,
+): ConversationSnapshot {
+  if (!requests) return snapshot;
+  let changed = false;
+  const nodes = snapshot.nodes.map((node) => {
+    if (node.kind !== 'message' || !node.clientRequestId) return node;
+    const nodeId = requests[node.clientRequestId]?.nodeId;
+    if (!nodeId || node.id === nodeId) return node;
+    changed = true;
+    return { ...node, id: nodeId };
+  });
+  return changed ? { ...snapshot, nodes } : snapshot;
+}
+
 function optimisticNode(
   nodeId: string,
   clientRequestId: string,
@@ -601,12 +617,16 @@ export function createCodingConversationStore(
         if (!current.reducer.invalidation && snapshotIsOlder(current.reducer.snapshot, snapshot)) {
           return state;
         }
+        const reconciledSnapshot = withReconciledOptimisticNodeIds(
+          snapshot,
+          state.requestsByConversationId[event.conversationId],
+        );
         const requests = withoutReconciledRequests(
           state.requestsByConversationId[event.conversationId],
-          snapshot,
+          reconciledSnapshot,
         );
         const reducer = withUnreconciledOptimisticNodes(
-          replaceConversationSnapshot(current.reducer, snapshot),
+          replaceConversationSnapshot(current.reducer, reconciledSnapshot),
           requests,
         );
         const entry: CodingConversationEntry = {

tests/unit/coding-conversations-store.test.tsx

@@ -337,6 +337,43 @@ describe('coding Conversation store', () => {
     expect(store.getState().requestsByConversationId['conversation-a']).toEqual({});
   });
 
+  it('preserves the optimistic UI id when a reconnect snapshot is already durable', async () => {
+    const store = createCodingConversationStore({
+      getSnapshot: vi.fn(),
+      openEvents: vi.fn(),
+      submitPrompt: vi.fn(async (input) => acceptance(
+        input.conversationId,
+        input.clientRequestId,
+      )),
+      createId: ids(),
+    });
+    store.getState().applySnapshotEvent(snapshotEvent(snapshot('conversation-a')));
+    store.getState().setDraft('conversation-a', 'Already durable');
+    await store.getState().submitPrompt({ conversationId: 'conversation-a', mode: 'prompt' });
+    const durable = snapshot('conversation-a', 1, 1);
+    store.getState().applySnapshotEvent(snapshotEvent({
+      ...durable,
+      nodes: [{
+        kind: 'message',
+        id: 'durable-user-1',
+        sourceEntryId: 'entry-user-1',
+        clientRequestId: 'request-1',
+        role: 'user',
+        status: 'complete',
+        blocks: [{ kind: 'text', id: 'durable-text-1', text: 'Already durable', status: 'complete' }],
+      }],
+    }));
+
+    expect(selectCodingConversationSnapshot('conversation-a')(store.getState())?.nodes[0])
+      .toMatchObject({
+        id: 'node-1',
+        sourceEntryId: 'entry-user-1',
+        clientRequestId: 'request-1',
+        status: 'complete',
+      });
+    expect(store.getState().requestsByConversationId['conversation-a']).toEqual({});
+  });
+
   it('restores draft attachments and marks the optimistic node on definite rejection', async () => {
     const submitPrompt = vi.fn(async () => {
       throw new AppError('RUNTIME', 'Model unavailable', undefined, {