migrate: replace Firebase with PostgreSQL across core routes

- chat-context.ts: session history now from fs_sessions
- /api/sessions: reads from fs_sessions (NextAuth session auth)
- /api/github/connect: NextAuth session + stores in fs_users.data
- /api/user/api-key: NextAuth session + stores in fs_users.data
- /api/projects/[id]/vision: PATCH to fs_projects JSONB
- /api/projects/[id]/knowledge/items: reads from fs_knowledge_items
- /api/projects/[id]/knowledge/import-ai-chat: uses pg createKnowledgeItem
- lib/server/knowledge.ts: fully rewritten to use PostgreSQL
- entrypoint.sh: add fs_knowledge_items and chat_conversations tables

Made-with: Cursor

lib/server/chat-context.ts

@@ -205,17 +205,15 @@ export async function buildProjectContextForChat(
     };
 
     try {
-      // Query sessions linked to this project
-      const sessionsSnapshot = await adminDb
-        .collection('sessions')
-        .where('projectId', '==', projectId)
-        .orderBy('startTime', 'asc')
-        .get();
+      // Query sessions linked to this project from PostgreSQL
+      const sessionRows = await query<{ id: string; data: any }>(
+        `SELECT id, data FROM fs_sessions WHERE data->>'projectId' = $1 ORDER BY created_at ASC`,
+        [projectId]
+      );
+
+      if (sessionRows.length > 0) {
+        sessionHistory.totalSessions = sessionRows.length;
 
-      if (!sessionsSnapshot.empty) {
-        sessionHistory.totalSessions = sessionsSnapshot.size;
-        
-        // Extract all messages from all sessions in chronological order
         const allMessages: Array<{
           role: string;
           content: string;
@@ -223,32 +221,27 @@ export async function buildProjectContextForChat(
           sessionId: string;
         }> = [];
 
-        for (const sessionDoc of sessionsSnapshot.docs) {
-          const sessionData = sessionDoc.data();
-          const conversation = sessionData.conversation || [];
-          
-          // Add messages from this session
+        for (const row of sessionRows) {
+          const conversation = row.data?.conversation || [];
           for (const msg of conversation) {
             if (msg.content && msg.content.trim()) {
               allMessages.push({
                 role: msg.role || 'unknown',
                 content: msg.content,
-                timestamp: msg.timestamp instanceof Date 
-                  ? msg.timestamp.toISOString() 
-                  : (typeof msg.timestamp === 'string' ? msg.timestamp : new Date().toISOString()),
-                sessionId: sessionDoc.id,
+                timestamp: typeof msg.timestamp === 'string'
+                  ? msg.timestamp
+                  : new Date().toISOString(),
+                sessionId: row.id,
               });
             }
           }
         }
 
-        // Sort all messages by timestamp (chronological order)
-        allMessages.sort((a, b) => 
+        allMessages.sort((a, b) =>
           new Date(a.timestamp).getTime() - new Date(b.timestamp).getTime()
         );
 
         sessionHistory.messages = allMessages;
-
         console.log(
           `[Chat Context] Loaded ${sessionHistory.totalSessions} sessions with ${allMessages.length} total messages for project ${projectId}`
         );