feat(07-01): DB migration 009, ORM updates, and LANGUAGE_INSTRUCTION in system prompts

- Migration 009: adds language col (VARCHAR 10, NOT NULL, default 'en') to portal_users
- Migration 009: adds translations col (JSONB, NOT NULL, default '{}') to agent_templates
- Migration 009: backfills es+pt translations for all 7 seed templates
- PortalUser ORM: language mapped column added
- AgentTemplate ORM: translations mapped column added
- system_prompt_builder.py: LANGUAGE_INSTRUCTION constant + appended before AI_TRANSPARENCY_CLAUSE
- system-prompt-builder.ts: LANGUAGE_INSTRUCTION constant + appended before AI transparency clause
- tests: TestLanguageInstruction class with 3 tests (all pass, 20 total)

tests/unit/test_system_prompt_builder.py

@@ -166,3 +166,43 @@ class TestBuildSystemPromptAIClauseAlwaysPresent:
     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
+
+
+class TestLanguageInstruction:
+    """LANGUAGE_INSTRUCTION must be present in all system prompts before AI transparency clause."""
+
+    LANGUAGE_INSTRUCTION = (
+        "Detect the language of each user message and respond in that same language. "
+        "You support English, Spanish, and Portuguese."
+    )
+
+    def test_language_instruction_present_in_default_prompt(self) -> None:
+        """build_system_prompt with name+role includes LANGUAGE_INSTRUCTION."""
+        prompt = build_system_prompt(name="Mara", role="Support Rep")
+        assert self.LANGUAGE_INSTRUCTION in prompt
+
+    def test_language_instruction_present_with_full_args(self) -> None:
+        """build_system_prompt with all args includes LANGUAGE_INSTRUCTION."""
+        prompt = build_system_prompt(
+            name="Mara",
+            role="Support Rep",
+            persona="Helpful and professional",
+            tool_assignments=["knowledge_base_search"],
+            escalation_rules=[{"condition": "billing_dispute", "action": "handoff_human"}],
+        )
+        assert self.LANGUAGE_INSTRUCTION in prompt
+
+    def test_language_instruction_before_transparency_clause(self) -> None:
+        """LANGUAGE_INSTRUCTION appears before AI_TRANSPARENCY_CLAUSE in the prompt."""
+        prompt = build_system_prompt(
+            name="Mara",
+            role="Support Rep",
+            persona="Helpful",
+            tool_assignments=["kb_search"],
+            escalation_rules=[{"condition": "x", "action": "handoff_human"}],
+        )
+        lang_pos = prompt.index(self.LANGUAGE_INSTRUCTION)
+        transparency_pos = prompt.index(AI_TRANSPARENCY_CLAUSE)
+        assert lang_pos < transparency_pos, (
+            "LANGUAGE_INSTRUCTION must appear before AI_TRANSPARENCY_CLAUSE"
+        )