Security fixes

auth.py

secrets.compare_digest replaces == for service key comparison (timing-safe)
Added require_service_key — bot-only endpoints (trip/event join/leave)
Added require_service_key_or_admin — node commands/config (bot via service key OR dashboard admin via Firebase)
Added _RateLimiter with three shared instances: trip_chat_limiter (20/5min per user), summarize_limiter (5/10min per incident), bootstrap_limiter (2/hr per system)
nodes.py

send_command and assign_system now require require_service_key_or_admin — the Discord bot can still call them via service key, but regular Firebase users are blocked
tokens.py

add_token, flush_tokens, set_preferred_system, delete_token all require require_admin_token
Token masking changed from token[:10] + "…" + token[-4:] to "•••" + token[-4:]
systems.py

All write endpoints (create, update, delete, ai-flags, ten-codes, vocabulary writes, bootstrap) now require require_admin_token
bootstrap_vocabulary also calls bootstrap_limiter.check(system_id)
incidents.py

POST /incidents/summarize (bulk) now requires require_admin_token
POST /incidents/{id}/summarize now calls summarize_limiter.check(incident_id)
trips.py

join_trip, leave_trip, join_event, leave_event require require_service_key — only the Discord bot can set Discord attendee identity
delete_trip, delete_event require require_service_key_or_admin
trip_chat rate-limited per caller UID, history stripped to user/assistant roles only, user message truncated to 2000 chars, Maps query strings capped at 200 chars
upload.py

Rejects files larger than settings.upload_max_bytes (default 100MB) with 413
storage.py

_safe_audio_filename() derives GCS object name from call_id + allowlisted extension, completely ignoring the client-supplied filename
config.py

Added upload_max_bytes: int = 100 * 1024 * 1024
Both Dockerfiles — python:3.14-slim → python:3.12-slim

drb-c2-core/app/routers/upload.py

@@ -4,6 +4,7 @@ from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
 from app.internal.storage import upload_audio
 from app.internal import firestore as fstore
 from app.internal.logger import logger
+from app.config import settings
 
 router = APIRouter(tags=["upload"])
 
@@ -43,9 +44,10 @@ async def upload_call_audio(
     data = await file.read()
     if not data:
         raise HTTPException(400, "Empty file.")
+    if len(data) > settings.upload_max_bytes:
+        raise HTTPException(413, f"File too large (max {settings.upload_max_bytes // (1024*1024)} MB).")
 
-    filename = file.filename
-    audio_url = await upload_audio(data, filename)
+    audio_url = await upload_audio(data, file.filename or "", call_id=call_id)
 
     if audio_url:
         try: