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/registry.py

@@ -100,5 +100,41 @@ class AgentRegistry:
     def get_agents_by_permission(self, permission: str) -> tuple[AgentConfig, ...]:
         return tuple(a for a in self._agents.values() if a.permission == permission)
 
+    @classmethod
+    def load_template(
+        cls,
+        template_name: str,
+        templates_dir: str | Path | None = None,
+    ) -> AgentRegistry:
+        """Load agent configurations from a named template."""
+        if templates_dir is None:
+            templates_dir = Path(__file__).parent.parent / "templates"
+        templates_dir = Path(templates_dir)
+
+        yaml_path = templates_dir / f"{template_name}.yaml"
+        if not yaml_path.exists():
+            available = cls.list_templates(templates_dir)
+            raise FileNotFoundError(
+                f"Template '{template_name}' not found. "
+                f"Available: {', '.join(available) if available else 'none'}"
+            )
+        return cls.load(yaml_path)
+
+    @classmethod
+    def list_templates(
+        cls,
+        templates_dir: str | Path | None = None,
+    ) -> tuple[str, ...]:
+        """List available template names from the templates directory."""
+        if templates_dir is None:
+            templates_dir = Path(__file__).parent.parent / "templates"
+        templates_dir = Path(templates_dir)
+
+        if not templates_dir.is_dir():
+            return ()
+        return tuple(
+            sorted(p.stem for p in templates_dir.glob("*.yaml"))
+        )
+
     def __len__(self) -> int:
         return len(self._agents)