feat: integrate pixel teacher presence and resilient classroom preview

src/stores/coding-conversations.ts

@@ -52,6 +52,8 @@ export interface SubmitCodingPromptInput {
   text?: string;
   attachments?: CodingDraftAttachment[];
   prepareAttachments?(): Promise<CodingDraftAttachment[]>;
+  /** Internal recovery uses durable conversation context, never the student's draft. */
+  preserveDraft?: boolean;
 }
 
 interface CodingConversationStoreDependencies {
@@ -167,18 +169,38 @@ function requestIdsInSnapshot(snapshot: ConversationSnapshot): Set<string> {
 function withoutReconciledRequests(
   requests: Record<string, CodingPromptRequestState> | undefined,
   snapshot: ConversationSnapshot,
+  reconciled = requestIdsInSnapshot(snapshot),
 ): Record<string, CodingPromptRequestState> {
-  const reconciled = requestIdsInSnapshot(snapshot);
   const requestUncertaintySettled = snapshot.run.status === 'idle' || snapshot.run.status === 'error';
   if (!requests || (reconciled.size === 0 && !requestUncertaintySettled)) return requests ?? {};
   return Object.fromEntries(
     Object.entries(requests).filter(([clientRequestId, request]) => (
       !reconciled.has(clientRequestId)
       && !(request.status === 'uncertain' && requestUncertaintySettled)
+      && !acceptedRunHasSettled(request, snapshot)
     )),
   );
 }
 
+function acceptedRunHasSettled(request: CodingPromptRequestState, snapshot: ConversationSnapshot): boolean {
+  return request.status === 'accepted' && Boolean(request.runId)
+    && request.runId === snapshot.run.runId && taskHasSettled(snapshot);
+}
+
+function withoutSettledOptimisticNodes(
+  reducer: ConversationReducerState,
+  requests: Record<string, CodingPromptRequestState> | undefined,
+): ConversationReducerState {
+  const snapshot = reducer.snapshot;
+  if (!snapshot || !requests) return reducer;
+  const nodes = snapshot.nodes.filter((node) => {
+    if (node.kind !== 'message' || node.status !== 'optimistic' || !node.clientRequestId) return true;
+    const request = requests[node.clientRequestId];
+    return !request || !acceptedRunHasSettled(request, snapshot);
+  });
+  return nodes.length === snapshot.nodes.length ? reducer : replaceConversationSnapshot(reducer, { ...snapshot, nodes });
+}
+
 function withReconciledOptimisticNodeIds(
   snapshot: ConversationSnapshot,
   requests: Record<string, CodingPromptRequestState> | undefined,
@@ -784,7 +806,7 @@ export function createCodingConversationStore(
           ),
           draftsByConversationId: {
             ...state.draftsByConversationId,
-            [input.conversationId]: { text: '', attachments: [], revision: clearedRevision },
+            ...(input.preserveDraft ? {} : { [input.conversationId]: { text: '', attachments: [], revision: clearedRevision } }),
           },
           requestsByConversationId: {
             ...state.requestsByConversationId,
@@ -846,14 +868,28 @@ export function createCodingConversationStore(
           const current = requests[clientRequestId];
           if (!current) return state;
           const nextRequests = { ...requests };
+          const entry = state.entriesByConversationId[input.conversationId];
+          let reducer = entry?.reducer;
           // Queued messages are projected by the authoritative queue; only a
           // prompt has an optimistic node awaiting clientRequestId reconciliation.
           if (current.mode === 'prompt') {
-            nextRequests[clientRequestId] = { ...current, status: 'accepted' };
+            const accepted: CodingPromptRequestState = { ...current, status: 'accepted', runId: acceptance.runId };
+            if (reducer?.snapshot && acceptedRunHasSettled(accepted, reducer.snapshot)) {
+              delete nextRequests[clientRequestId];
+              reducer = withoutSettledOptimisticNodes(reducer, { [clientRequestId]: accepted });
+            } else {
+              nextRequests[clientRequestId] = accepted;
+            }
           } else {
             delete nextRequests[clientRequestId];
           }
           return {
+            ...(entry && reducer !== entry.reducer ? {
+              entriesByConversationId: {
+                ...state.entriesByConversationId,
+                [input.conversationId]: { ...entry, reducer: reducer! },
+              },
+            } : {}),
             requestsByConversationId: {
               ...state.requestsByConversationId,
               [input.conversationId]: nextRequests,
@@ -869,7 +905,7 @@ export function createCodingConversationStore(
           const requests = state.requestsByConversationId[input.conversationId] ?? {};
           const currentRequest = requests[clientRequestId] ?? request;
           const currentDraft = state.draftsByConversationId[input.conversationId] ?? DEFAULT_DRAFT;
-          const canRestore = currentDraft.revision === clearedRevision
+          const canRestore = !input.preserveDraft && currentDraft.revision === clearedRevision
             && !currentDraft.text
             && currentDraft.attachments.length === 0;
           const reducer = uncertain
@@ -937,7 +973,10 @@ export function createCodingConversationStore(
           reconciledSnapshot,
         );
         const reducer = withUnreconciledOptimisticNodes(
-          replaceConversationSnapshot(current.reducer, reconciledSnapshot),
+          withoutSettledOptimisticNodes(
+            replaceConversationSnapshot(current.reducer, reconciledSnapshot),
+            state.requestsByConversationId[event.conversationId],
+          ),
           requests,
         );
         const entry: CodingConversationEntry = {
@@ -1022,6 +1061,16 @@ export function createCodingConversationStore(
         }
         if (reducer === current.reducer) return state;
         applied = true;
+        const requests = state.requestsByConversationId[applicableEvent.conversationId] ?? {};
+        // The reduced snapshot also contains Renderer optimistic nodes. Only
+        // request ids delivered in this Main patch batch count as receipt evidence.
+        const authoritativeRequestIds = new Set(applicableEvent.items.flatMap(({ patch }) => (
+          patch.op === 'message.upsert' && patch.node.clientRequestId ? [patch.node.clientRequestId] : []
+        )));
+        const nextRequests = reducer.snapshot
+          ? withoutReconciledRequests(requests, reducer.snapshot, authoritativeRequestIds)
+          : requests;
+        reducer = withoutSettledOptimisticNodes(reducer, requests);
         const unread = state.selectedConversationId !== applicableEvent.conversationId
           && newlyNeedsUserAttention(current.reducer.snapshot, reducer.snapshot)
             ? true
@@ -1033,10 +1082,6 @@ export function createCodingConversationStore(
           error: null,
           unread,
         };
-        const requests = state.requestsByConversationId[applicableEvent.conversationId] ?? {};
-        const nextRequests = reducer.snapshot
-          ? withoutReconciledRequests(requests, reducer.snapshot)
-          : requests;
         const requestsChanged = Object.keys(nextRequests).length !== Object.keys(requests).length;
         return {
           entriesByConversationId: {