fix: close PI core chat review gaps

electron/api/coding-composition.ts

@@ -81,7 +81,18 @@ export function createCodingComposition(
   });
   const extensionHost = new PiManagedExtensionHost();
   extensionHost.configureProductTools(productTools);
-  const registry = new PiSessionRegistry({ projectStore });
+  const conversationStores = new Map<string, ReturnType<typeof createCodingConversationStore>>();
+  const conversationStoreForProject = (projectPath: string) => {
+    const existing = conversationStores.get(projectPath);
+    if (existing) return existing;
+    const created = createCodingConversationStore(projectPath);
+    conversationStores.set(projectPath, created);
+    return created;
+  };
+  const registry = new PiSessionRegistry({
+    projectStore,
+    createConversationStore: conversationStoreForProject,
+  });
   const revisions = new PiManagedInputRevisionCoordinator();
   const processBudget = new PiProcessBudget();
   const loadProviderInput = async () => ({
@@ -145,15 +156,16 @@ export function createCodingComposition(
     })),
   });
   const projects = new CodingProjectService(projectStore, {
+    createConversationStore: conversationStoreForProject,
     onResourcesChanged: async (project) => {
       runtime.markResourcesStale();
-      const conversations = await createCodingConversationStore(project.path).read()
+      const conversations = await conversationStoreForProject(project.path).read()
         .then((file) => file.conversations)
         .catch(() => []);
       for (const conversation of conversations) registry.forget(conversation.id);
     },
     onProjectDeactivated: async (project) => {
-      const conversations = await createCodingConversationStore(project.path).read()
+      const conversations = await conversationStoreForProject(project.path).read()
         .then((file) => file.conversations)
         .catch(() => []);
       await Promise.allSettled([

electron/api/routes/coding-attachments.ts

@@ -3,6 +3,7 @@ import type { HostApiContext } from '../context';
 import { sendJson } from '../route-utils';
 
 const MAX_ATTACHMENT_BYTES = 16 * 1024 * 1024;
+const ATTACHMENT_ID_PATTERN = /^[A-Za-z0-9-]{1,64}$/;
 const SUPPORTED_IMAGE_MIMES = new Set([
   'image/png',
   'image/jpeg',
@@ -10,6 +11,37 @@ const SUPPORTED_IMAGE_MIMES = new Set([
   'image/gif',
 ]);
 
+function matchesImageSignature(data: Uint8Array, mime: string): boolean {
+  if (mime === 'image/png') {
+    return data.length >= 8
+      && data[0] === 0x89
+      && data[1] === 0x50
+      && data[2] === 0x4e
+      && data[3] === 0x47
+      && data[4] === 0x0d
+      && data[5] === 0x0a
+      && data[6] === 0x1a
+      && data[7] === 0x0a;
+  }
+  if (mime === 'image/jpeg') {
+    return data.length >= 3
+      && data[0] === 0xff
+      && data[1] === 0xd8
+      && data[2] === 0xff;
+  }
+  if (mime === 'image/gif') {
+    if (data.length < 6) return false;
+    const header = Buffer.from(data.subarray(0, 6)).toString('ascii');
+    return header === 'GIF87a' || header === 'GIF89a';
+  }
+  if (mime === 'image/webp') {
+    return data.length >= 12
+      && Buffer.from(data.subarray(0, 4)).toString('ascii') === 'RIFF'
+      && Buffer.from(data.subarray(8, 12)).toString('ascii') === 'WEBP';
+  }
+  return false;
+}
+
 function contentType(req: IncomingMessage): string {
   const value = req.headers['content-type'];
   return (Array.isArray(value) ? value[0] : value)?.split(';', 1)[0]?.trim().toLowerCase() ?? '';
@@ -17,7 +49,7 @@ function contentType(req: IncomingMessage): string {
 
 async function readBoundedBody(req: IncomingMessage): Promise<Uint8Array> {
   const declared = Number(req.headers['content-length']);
-  if (Number.isFinite(declared) && (declared <= 0 || declared > MAX_ATTACHMENT_BYTES)) {
+  if (Number.isFinite(declared) && declared > MAX_ATTACHMENT_BYTES) {
     throw Object.assign(new Error('Attachment size is invalid'), { status: 413 });
   }
   const chunks: Buffer[] = [];
@@ -86,12 +118,24 @@ export async function handleCodingAttachmentRoutes(
       if (!SUPPORTED_IMAGE_MIMES.has(mime)) {
         throw Object.assign(new Error('Attachment MIME is invalid'), { status: 400 });
       }
-      const attachment = await attachments.put(await readBoundedBody(req), mime);
+      const body = await readBoundedBody(req);
+      if (!matchesImageSignature(body, mime)) {
+        throw Object.assign(new Error('Attachment body is not the declared image type'), { status: 400 });
+      }
+      const attachment = await attachments.put(body, mime);
       sendJson(res, 201, attachment);
       return true;
     }
 
-    const attachmentId = decodeURIComponent(contentMatch?.[1] ?? '');
+    let attachmentId: string;
+    try {
+      attachmentId = decodeURIComponent(contentMatch?.[1] ?? '');
+    } catch {
+      throw Object.assign(new Error('Attachment id is invalid'), { status: 400 });
+    }
+    if (!ATTACHMENT_ID_PATTERN.test(attachmentId)) {
+      throw Object.assign(new Error('Attachment id is invalid'), { status: 400 });
+    }
     const record = await attachments.read(attachmentId);
     if (!SUPPORTED_IMAGE_MIMES.has(record.mime)) {
       throw Object.assign(new Error('Attachment MIME is invalid'), { status: 400 });

electron/api/server.ts

@@ -56,9 +56,12 @@ export function startHostApiServer(ctx: HostApiContext, port = getPort('NIANCODE
       }
 
       // ── Content-Type gate (anti-CSRF) ──────────────────────────
-      // Mutation requests must use application/json to force a CORS
-      // preflight, preventing "simple request" CSRF attacks.
-      if (!requireJsonContentType(req)) {
+      // Mutation requests use application/json, except the exact authenticated
+      // image-byte upload route. Its supported image MIME types also force a
+      // browser preflight and are validated before storage.
+      const isCodingAttachmentUpload = req.method === 'POST'
+        && requestUrl.pathname === '/api/coding/attachments';
+      if (!isCodingAttachmentUpload && !requireJsonContentType(req)) {
         sendJson(res, 415, { success: false, error: 'Content-Type must be application/json' });
         return;
       }

electron/coding-projects/project-service.ts

@@ -56,6 +56,7 @@ export interface CodingProjectConfigSnapshot {
 export interface CodingProjectServiceOptions {
   onResourcesChanged?(project: CodingProject): Promise<void> | void;
   onProjectDeactivated?(project: CodingProject): Promise<void> | void;
+  createConversationStore?: typeof createCodingConversationStore;
   writeConfig?: typeof writeCodingProjectConfigV2;
 }
 
@@ -299,7 +300,7 @@ export class CodingProjectService {
   conversationStore(projectPath: string): ReturnType<typeof createCodingConversationStore> {
     const existing = this.conversationStores.get(projectPath);
     if (existing) return existing;
-    const created = createCodingConversationStore(projectPath);
+    const created = (this.options.createConversationStore ?? createCodingConversationStore)(projectPath);
     this.conversationStores.set(projectPath, created);
     return created;
   }