Rename: jarvisChat → cAIc (product name)

- jarvisChat/JarvisChat/jarvischat → cAIc/cAIc/caic (branded/lower)
- JARVISCHAT_ env vars → CAIC_
- jc- script/config prefix → caic-
- jarvis_rag → caic_rag
- jarvischat.db / volumes → caic.db / caic_*
- AMQP vhost/user jarvischat → caic
- Syslog, loggers, docstrings all updated
- 47 files, zero stale references, 148 tests pass

routers/completions.py

@@ -20,7 +20,7 @@ from db import get_db
 from rag import build_system_prompt
 from routers.chat import parse_llama_stream_chunk
 
-log = logging.getLogger("jarvischat")
+log = logging.getLogger("caic")
 router = APIRouter()