Initial project structure

Scaffold all modules, route stubs, data models, and config.
No logic implemented yet — all core methods raise NotImplementedError.
Establishes the full directory layout matching the architecture in CLAUDE.md.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.env.example

@@ -0,0 +1,14 @@
+# LLM Backend
+LLM_BASE_URL=http://localhost:8080/v1
+LLM_API_KEY=not-needed
+
+# Models
+DEFAULT_BOT_MODEL=your-model-name
+DEFAULT_ORCHESTRATOR_MODEL=your-model-name
+
+# Server Limits
+MAX_BOTS_PER_SESSION=10
+SESSION_TTL_DEFAULT=3600
+
+# Debug
+DEBUG=false