feat: complete phase 2 -- multi-agent routing, interrupt TTL, escalation, templates

- Intent classification with LLM structured output (single/multi/ambiguous)
- Discount agent with apply_discount and generate_coupon tools
- Interrupt manager with 30-min TTL auto-expiration and retry prompts
- Webhook escalation module with exponential backoff retry (max 3)
- Three vertical industry templates (e-commerce, SaaS, fintech)
- Template loading in AgentRegistry
- Enhanced supervisor prompt with dynamic agent descriptions
- 153 tests passing, 90.18% coverage

backend/app/config.py

@@ -26,6 +26,12 @@ class Settings(BaseSettings):
     ws_host: str = "0.0.0.0"
     ws_port: int = 8000
 
+    webhook_url: str = ""
+    webhook_timeout_seconds: int = 10
+    webhook_max_retries: int = 3
+
+    template_name: str = ""
+
     anthropic_api_key: str = ""
     openai_api_key: str = ""
     google_api_key: str = ""