security: v1.7.7 hardening release

- Add WEBHOOK_CLIENT_SECRET validation for Graph webhooks
- Add Redis-backed rate limiting (fetch/ask/write/default tiers)
- Validate LLM_BASE_URL to prevent SSRF (HTTPS only, block private IPs)
- Enforce non-wildcard CORS when AUTH_ENABLED=true
- Add Content-Security-Policy headers
- Fix audit middleware to use verified JWT claims via contextvars
- Cap bulk_tags updates to 10,000 documents
- Return generic error messages to clients (no internal detail leakage)
- Strict AlertCondition Pydantic model for alert rules
- Security warning on MCP stdio server startup
- Remove MongoDB/Redis host ports from docker-compose
- Remove mongo_query from /ask API response

backend/models/api.py

@@ -63,12 +63,18 @@ class CommentAddRequest(BaseModel):
     text: str
 
 
+class AlertCondition(BaseModel):
+    field: str
+    op: str  # eq, neq, contains, in, after_hours
+    value: str | list[str] | None = None
+
+
 class AlertRuleResponse(BaseModel):
     id: str | None = None
     name: str
     enabled: bool
     severity: str
-    conditions: list[dict]
+    conditions: list[AlertCondition]
     message: str