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_interrupt_manager.py

@@ -0,0 +1,132 @@
+"""Tests for app.interrupt_manager module."""
+
+from __future__ import annotations
+
+from unittest.mock import patch
+
+import pytest
+
+from app.interrupt_manager import InterruptManager
+
+
+@pytest.mark.unit
+class TestInterruptManagerRegister:
+    def test_register_creates_record(self) -> None:
+        mgr = InterruptManager(ttl_seconds=1800)
+        record = mgr.register("t1", "cancel_order", {"order_id": "1042"})
+        assert record.thread_id == "t1"
+        assert record.action == "cancel_order"
+        assert record.ttl_seconds == 1800
+        assert record.interrupt_id
+
+    def test_register_overwrites_previous(self) -> None:
+        mgr = InterruptManager()
+        r1 = mgr.register("t1", "cancel_order", {})
+        r2 = mgr.register("t1", "apply_discount", {})
+        assert r1.interrupt_id != r2.interrupt_id
+        status = mgr.check_status("t1")
+        assert status is not None
+        assert status.record.action == "apply_discount"
+
+
+@pytest.mark.unit
+class TestInterruptManagerCheckStatus:
+    def test_no_interrupt_returns_none(self) -> None:
+        mgr = InterruptManager()
+        assert mgr.check_status("t1") is None
+
+    def test_fresh_interrupt_not_expired(self) -> None:
+        mgr = InterruptManager(ttl_seconds=1800)
+        mgr.register("t1", "cancel_order", {})
+        status = mgr.check_status("t1")
+        assert status is not None
+        assert not status.is_expired
+        assert status.remaining_seconds > 0
+
+    def test_expired_interrupt(self) -> None:
+        mgr = InterruptManager(ttl_seconds=10)
+        mgr.register("t1", "cancel_order", {})
+        # Move time forward
+        with patch("app.interrupt_manager.time") as mock_time:
+            mock_time.time.return_value = mgr._interrupts["t1"].created_at + 11
+            status = mgr.check_status("t1")
+            assert status is not None
+            assert status.is_expired
+            assert status.remaining_seconds == 0.0
+
+    def test_boundary_not_expired(self) -> None:
+        mgr = InterruptManager(ttl_seconds=10)
+        mgr.register("t1", "cancel_order", {})
+        with patch("app.interrupt_manager.time") as mock_time:
+            mock_time.time.return_value = mgr._interrupts["t1"].created_at + 9
+            status = mgr.check_status("t1")
+            assert status is not None
+            assert not status.is_expired
+
+
+@pytest.mark.unit
+class TestInterruptManagerResolve:
+    def test_resolve_removes_record(self) -> None:
+        mgr = InterruptManager()
+        mgr.register("t1", "cancel_order", {})
+        mgr.resolve("t1")
+        assert mgr.check_status("t1") is None
+
+    def test_resolve_nonexistent_is_safe(self) -> None:
+        mgr = InterruptManager()
+        mgr.resolve("nonexistent")  # Should not raise
+
+
+@pytest.mark.unit
+class TestInterruptManagerCleanup:
+    def test_cleanup_removes_expired(self) -> None:
+        mgr = InterruptManager(ttl_seconds=5)
+        mgr.register("t1", "cancel_order", {})
+        mgr.register("t2", "apply_discount", {})
+
+        with patch("app.interrupt_manager.time") as mock_time:
+            mock_time.time.return_value = mgr._interrupts["t1"].created_at + 6
+            expired = mgr.cleanup_expired()
+            assert len(expired) == 2
+            assert mgr.check_status("t1") is None
+            assert mgr.check_status("t2") is None
+
+    def test_cleanup_keeps_active(self) -> None:
+        mgr = InterruptManager(ttl_seconds=100)
+        mgr.register("t1", "cancel_order", {})
+
+        expired = mgr.cleanup_expired()
+        assert len(expired) == 0
+        assert mgr.check_status("t1") is not None
+
+
+@pytest.mark.unit
+class TestInterruptManagerRetryPrompt:
+    def test_generates_correct_prompt(self) -> None:
+        mgr = InterruptManager(ttl_seconds=1800)
+        record = mgr.register("t1", "cancel_order", {"order_id": "1042"})
+        prompt = mgr.generate_retry_prompt(record)
+        assert prompt["type"] == "interrupt_expired"
+        assert prompt["thread_id"] == "t1"
+        assert prompt["action"] == "cancel_order"
+        assert "30 minutes" in prompt["message"]
+        assert "cancel_order" in prompt["message"]
+
+
+@pytest.mark.unit
+class TestInterruptManagerHasPending:
+    def test_no_interrupt(self) -> None:
+        mgr = InterruptManager()
+        assert not mgr.has_pending("t1")
+
+    def test_has_active_interrupt(self) -> None:
+        mgr = InterruptManager(ttl_seconds=1800)
+        mgr.register("t1", "cancel_order", {})
+        assert mgr.has_pending("t1")
+
+    def test_expired_interrupt_not_pending(self) -> None:
+        mgr = InterruptManager(ttl_seconds=5)
+        mgr.register("t1", "cancel_order", {})
+        with patch("app.interrupt_manager.time") as mock_time:
+            mock_time.time.return_value = mgr._interrupts["t1"].created_at + 6
+            assert not mgr.has_pending("t1")