Record sent chats in messages repo and blur gallery by default

Threads MessagesRepository through ChatService so first outgoing chat
messages are persisted for stats, and extends the repo + DB client to
support chat-room-keyed lookups. Adds tests covering the new behavior.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/database.test.ts

@@ -130,7 +130,8 @@ describe('Database Client', () => {
       expect(columnMap.get('subject')?.notnull).toBe(1);
       expect(columnMap.get('message')?.notnull).toBe(1);
       expect(columnMap.get('sent_at')?.notnull).toBe(1);
-      expect(columnMap.get('post_id')?.notnull).toBe(1);
+      expect(columnMap.get('post_id')?.notnull).toBe(0); // nullable — chat rows have no post
+      expect(columnMap.get('chat_room_id')).toBeDefined();
     });
 
     it('successful_messages has correct schema', () => {

tests/repositories.test.ts

@@ -171,6 +171,40 @@ describe('MessagesRepository', () => {
     db = repos.db;
   });
 
+  it('insertChat stores a chat-originated send and getByChatRoomId returns it', () => {
+    const id = messagesRepo.insertChat({
+      recipient: 'alice',
+      subject: 'alice',
+      message: 'hey there',
+      sentAt: 1700000000000,
+      chatRoomId: '!room123:reddit.com',
+    });
+    expect(id).toBeGreaterThan(0);
+
+    const row = messagesRepo.getByChatRoomId('!room123:reddit.com');
+    expect(row).toBeDefined();
+    expect(row!.postId).toBeNull();
+    expect(row!.chatRoomId).toBe('!room123:reddit.com');
+    expect(row!.recipient).toBe('alice');
+    expect(row!.gotResponse).toBe(false);
+
+    messagesRepo.markGotResponse(id);
+    const updated = messagesRepo.getByChatRoomId('!room123:reddit.com');
+    expect(updated!.gotResponse).toBe(true);
+  });
+
+  it('chat-originated rows appear in getRecent and contribute to stats', () => {
+    messagesRepo.insertChat({
+      recipient: 'bob',
+      subject: 'bob',
+      message: 'hi',
+      sentAt: Date.now(),
+      chatRoomId: '!r1:reddit.com',
+    });
+    const recent = messagesRepo.getRecent(10);
+    expect(recent.some((m) => m.chatRoomId === '!r1:reddit.com')).toBe(true);
+  });
+
   it('inserts and retrieves a message', () => {
     const messageId = messagesRepo.insert({
       postId: 'post1',