feat(05-01): AgentTemplate ORM model, migration 007, and system prompt builder

- Add AgentTemplate ORM model to tenant.py (global, not tenant-scoped)
- Create migration 007 with agent_templates table and 7 seed templates
- Create shared/prompts/system_prompt_builder.py with build_system_prompt()
- AI transparency clause always present (non-negotiable per Phase 1 decision)
- Unit tests pass (17 tests, all sections verified)

tests/unit/test_system_prompt_builder.py

@@ -0,0 +1,168 @@
+"""
+Unit tests for shared.prompts.system_prompt_builder.
+
+Tests verify:
+- Full prompt with all fields produces expected sections
+- Minimal prompt (name + role only) still includes AI transparency clause
+- Empty tools and escalation_rules omit those sections
+- AI transparency clause is always present regardless of inputs
+"""
+
+from __future__ import annotations
+
+import pytest
+
+from shared.prompts.system_prompt_builder import build_system_prompt
+
+AI_TRANSPARENCY_CLAUSE = "When directly asked if you are an AI, always disclose that you are an AI assistant."
+
+
+class TestBuildSystemPromptFull:
+    """Test build_system_prompt with all fields populated."""
+
+    def test_contains_name(self) -> None:
+        prompt = build_system_prompt(
+            name="Mara",
+            role="Customer Support",
+            persona="Friendly and helpful",
+            tool_assignments=["knowledge_base_search"],
+            escalation_rules=[{"condition": "billing_dispute AND attempts > 2", "action": "handoff_human"}],
+        )
+        assert "You are Mara" in prompt
+
+    def test_contains_role(self) -> None:
+        prompt = build_system_prompt(
+            name="Mara",
+            role="Customer Support",
+            persona="Friendly and helpful",
+            tool_assignments=["knowledge_base_search"],
+            escalation_rules=[{"condition": "billing_dispute AND attempts > 2", "action": "handoff_human"}],
+        )
+        assert "Customer Support" in prompt
+
+    def test_contains_persona(self) -> None:
+        prompt = build_system_prompt(
+            name="Mara",
+            role="Customer Support",
+            persona="Friendly and helpful",
+            tool_assignments=["knowledge_base_search"],
+            escalation_rules=[{"condition": "billing_dispute AND attempts > 2", "action": "handoff_human"}],
+        )
+        assert "Friendly and helpful" in prompt
+
+    def test_contains_tool(self) -> None:
+        prompt = build_system_prompt(
+            name="Mara",
+            role="Customer Support",
+            persona="Friendly and helpful",
+            tool_assignments=["knowledge_base_search"],
+            escalation_rules=[{"condition": "billing_dispute AND attempts > 2", "action": "handoff_human"}],
+        )
+        assert "knowledge_base_search" in prompt
+
+    def test_contains_escalation_rule(self) -> None:
+        prompt = build_system_prompt(
+            name="Mara",
+            role="Customer Support",
+            persona="Friendly and helpful",
+            tool_assignments=["knowledge_base_search"],
+            escalation_rules=[{"condition": "billing_dispute AND attempts > 2", "action": "handoff_human"}],
+        )
+        assert "billing_dispute AND attempts > 2" in prompt
+
+    def test_contains_ai_transparency_clause(self) -> None:
+        prompt = build_system_prompt(
+            name="Mara",
+            role="Customer Support",
+            persona="Friendly and helpful",
+            tool_assignments=["knowledge_base_search"],
+            escalation_rules=[{"condition": "billing_dispute AND attempts > 2", "action": "handoff_human"}],
+        )
+        assert AI_TRANSPARENCY_CLAUSE in prompt
+
+
+class TestBuildSystemPromptMinimal:
+    """Test build_system_prompt with only name and role provided."""
+
+    def test_minimal_contains_name(self) -> None:
+        prompt = build_system_prompt(name="Alex", role="Sales Assistant")
+        assert "You are Alex" in prompt
+
+    def test_minimal_contains_role(self) -> None:
+        prompt = build_system_prompt(name="Alex", role="Sales Assistant")
+        assert "Sales Assistant" in prompt
+
+    def test_minimal_contains_ai_transparency_clause(self) -> None:
+        prompt = build_system_prompt(name="Alex", role="Sales Assistant")
+        assert AI_TRANSPARENCY_CLAUSE in prompt
+
+    def test_minimal_is_string(self) -> None:
+        prompt = build_system_prompt(name="Alex", role="Sales Assistant")
+        assert isinstance(prompt, str)
+        assert len(prompt) > 0
+
+
+class TestBuildSystemPromptEmptySections:
+    """Test that empty tools and escalation_rules omit those sections."""
+
+    def test_empty_tools_omits_tools_section(self) -> None:
+        prompt = build_system_prompt(
+            name="Bob",
+            role="Office Manager",
+            persona="Organized and efficient",
+            tool_assignments=[],
+            escalation_rules=[],
+        )
+        # Should not contain a tools header/section
+        assert "tools:" not in prompt.lower() or "tools" not in prompt.split("\n")[0]
+
+    def test_empty_escalation_omits_escalation_section(self) -> None:
+        prompt = build_system_prompt(
+            name="Bob",
+            role="Office Manager",
+            persona="Organized and efficient",
+            tool_assignments=[],
+            escalation_rules=[],
+        )
+        # Should not contain an escalation section
+        assert "Escalation" not in prompt
+
+    def test_none_tools_omits_tools_section(self) -> None:
+        prompt = build_system_prompt(
+            name="Bob",
+            role="Office Manager",
+            tool_assignments=None,
+            escalation_rules=None,
+        )
+        assert "Escalation" not in prompt
+
+    def test_empty_still_has_ai_transparency(self) -> None:
+        prompt = build_system_prompt(
+            name="Bob",
+            role="Office Manager",
+            tool_assignments=[],
+            escalation_rules=[],
+        )
+        assert AI_TRANSPARENCY_CLAUSE in prompt
+
+
+class TestBuildSystemPromptAIClauseAlwaysPresent:
+    """AI transparency clause must always be present — non-negotiable."""
+
+    def test_ai_clause_present_full_args(self) -> None:
+        prompt = build_system_prompt(
+            name="Mara",
+            role="Support",
+            persona="Helpful",
+            tool_assignments=["kb_search"],
+            escalation_rules=[{"condition": "x", "action": "handoff_human"}],
+        )
+        assert AI_TRANSPARENCY_CLAUSE in prompt
+
+    def test_ai_clause_present_name_role_only(self) -> None:
+        prompt = build_system_prompt(name="Z", role="Y")
+        assert AI_TRANSPARENCY_CLAUSE in prompt
+
+    def test_ai_clause_present_with_persona_only(self) -> None:
+        prompt = build_system_prompt(name="Sam", role="Analyst", persona="Detail-oriented")
+        assert AI_TRANSPARENCY_CLAUSE in prompt