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/tests/unit/test_templates.py

@@ -0,0 +1,70 @@
+"""Tests for template loading in app.registry."""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+
+from app.registry import AgentRegistry
+
+TEMPLATES_DIR = Path(__file__).parent.parent.parent / "templates"
+
+
+@pytest.mark.unit
+class TestListTemplates:
+    def test_lists_all_templates(self) -> None:
+        templates = AgentRegistry.list_templates(TEMPLATES_DIR)
+        assert "e-commerce" in templates
+        assert "saas" in templates
+        assert "fintech" in templates
+
+    def test_returns_sorted(self) -> None:
+        templates = AgentRegistry.list_templates(TEMPLATES_DIR)
+        assert templates == tuple(sorted(templates))
+
+    def test_empty_dir_returns_empty(self, tmp_path: Path) -> None:
+        templates = AgentRegistry.list_templates(tmp_path)
+        assert templates == ()
+
+    def test_nonexistent_dir_returns_empty(self) -> None:
+        templates = AgentRegistry.list_templates("/nonexistent/path")
+        assert templates == ()
+
+
+@pytest.mark.unit
+class TestLoadTemplate:
+    def test_load_ecommerce(self) -> None:
+        registry = AgentRegistry.load_template("e-commerce", TEMPLATES_DIR)
+        assert len(registry) == 4
+        agents = registry.list_agents()
+        names = {a.name for a in agents}
+        assert "order_lookup" in names
+        assert "discount" in names
+        assert "fallback" in names
+
+    def test_load_saas(self) -> None:
+        registry = AgentRegistry.load_template("saas", TEMPLATES_DIR)
+        assert len(registry) == 3
+        agents = registry.list_agents()
+        names = {a.name for a in agents}
+        assert "account_lookup" in names
+        assert "subscription_management" in names
+
+    def test_load_fintech(self) -> None:
+        registry = AgentRegistry.load_template("fintech", TEMPLATES_DIR)
+        assert len(registry) == 3
+        agents = registry.list_agents()
+        names = {a.name for a in agents}
+        assert "transaction_lookup" in names
+        assert "dispute_handler" in names
+
+    def test_nonexistent_template_raises(self) -> None:
+        with pytest.raises(FileNotFoundError, match="not found"):
+            AgentRegistry.load_template("nonexistent", TEMPLATES_DIR)
+
+    def test_error_message_lists_available(self) -> None:
+        try:
+            AgentRegistry.load_template("nonexistent", TEMPLATES_DIR)
+        except FileNotFoundError as exc:
+            assert "e-commerce" in str(exc)