Design HTTP parity for service_mgmt operations

[kanghengliu]

Parent: #247

Goal

Document the exact HTTP resources, request/response schemas, and auth requirements needed to replace cli/service_mgmt.sh (add/delete/monitor/test/add-to-groups/remove-from-groups/create-group/delete-group/list-groups) and its side-effects (FAISS metadata refresh, scopes.yml updates in both container + host) with first-class management APIs.

Deliverables

• Inventory of every script command, flag, and environment dependency.
• Proposed API surface (paths, verbs, payloads, success/error models) with scope requirements per operation.
• Plan for how FAISS + scopes refreshes are triggered via API instead of docker exec.
• Identification of migrations needed for existing callers (cli/mcp_client.py, docs, CI jobs).