feat: add LLM abstraction layer (router, Ollama backend, Claude backend)

agent_service/llm/llm_config_store.py

@@ -0,0 +1,35 @@
+from __future__ import annotations
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class LLMConfigStore:
+    def __init__(self, pg_pool):
+        self._pool = pg_pool
+
+    async def get_backend(self, caller):
+        async with self._pool.acquire(timeout=10) as conn:
+            row = await conn.fetchrow(
+                'SELECT backend FROM ab_llm_config WHERE caller = $1', caller)
+            return row['backend'] if row else None
+
+    async def set_backend(self, caller, backend, set_by, note=None):
+        async with self._pool.acquire(timeout=10) as conn:
+            await conn.execute(
+                """INSERT INTO ab_llm_config (caller, backend, set_by, note)
+                   VALUES ($1, $2, $3, $4)
+                   ON CONFLICT (caller) DO UPDATE
+                     SET backend=$2, set_by=$3, set_at=NOW(), note=$4""",
+                caller, backend, set_by, note)
+        logger.info('LLMConfigStore.set_backend caller=%s backend=%s set_by=%s', caller, backend, set_by)
+
+    async def get_all(self):
+        async with self._pool.acquire(timeout=10) as conn:
+            rows = await conn.fetch('SELECT * FROM ab_llm_config ORDER BY caller')
+            return [dict(r) for r in rows]
+
+    async def reset(self, caller):
+        async with self._pool.acquire(timeout=10) as conn:
+            await conn.execute('DELETE FROM ab_llm_config WHERE caller = $1', caller)
+        logger.info('LLMConfigStore.reset caller=%s', caller)