feat: add Atlas PRD agent for product discovery

- src/prompts/atlas.ts — full Atlas system prompt (6-phase PM discovery flow)
- src/tools/prd.ts — finalize_prd tool that signals PRD completion
- src/agents/atlas.ts — Atlas agent config (Tier A, conversational)
- src/atlas.ts — atlasChat() multi-turn session handler
- server.ts — /atlas/chat, /atlas/sessions endpoints

Made-with: Cursor

src/server.ts

@@ -10,6 +10,7 @@ import { AGENTS } from './agents';
 import { ToolContext } from './tools';
 import { PROTECTED_GITEA_REPOS } from './tools/security';
 import { orchestratorChat, listSessions, clearSession } from './orchestrator';
+import { atlasChat, listAtlasSessions, clearAtlasSession } from './atlas';
 import { LLMMessage } from './llm';
 
 const app = express();
@@ -216,6 +217,43 @@ app.delete('/orchestrator/sessions/:id', (req: Request, res: Response) => {
     res.json({ cleared: req.params.id });
 });
 
+// ---------------------------------------------------------------------------
+// Atlas — PRD discovery agent
+// ---------------------------------------------------------------------------
+
+app.post('/atlas/chat', async (req: Request, res: Response) => {
+    const {
+        message,
+        session_id,
+        history
+    } = req.body as {
+        message?: string;
+        session_id?: string;
+        history?: LLMMessage[];
+    };
+
+    if (!message) { res.status(400).json({ error: '"message" is required' }); return; }
+
+    const sessionId = session_id || `atlas_${Date.now()}`;
+    const ctx = buildContext();
+
+    try {
+        const result = await atlasChat(sessionId, message, ctx, { preloadedHistory: history });
+        res.json(result);
+    } catch (err) {
+        res.status(500).json({ error: err instanceof Error ? err.message : String(err) });
+    }
+});
+
+app.get('/atlas/sessions', (_req: Request, res: Response) => {
+    res.json(listAtlasSessions());
+});
+
+app.delete('/atlas/sessions/:id', (req: Request, res: Response) => {
+    clearAtlasSession(req.params.id);
+    res.json({ cleared: req.params.id });
+});
+
 // List recent jobs
 app.get('/api/jobs', (req: Request, res: Response) => {
     const limit = parseInt((req.query.limit as string) || '20', 10);