Add Hermes Workspace compatibility endpoints to api_server

[zjw200056061816-collab]

What

This extends gateway/platforms/api_server.py with the Hermes-native /api/* endpoints Hermes Workspace expects for enhanced mode.

Added:

• session APIs
  • GET/POST /api/sessions
  • GET /api/sessions/search
  • GET/PATCH/DELETE /api/sessions/{session_id}
  • GET /api/sessions/{session_id}/messages
  • POST /api/sessions/{session_id}/fork
  • POST /api/sessions/{session_id}/chat
  • POST /api/sessions/{session_id}/chat/stream
• skills APIs
  • GET /api/skills
  • GET /api/skills/categories
  • GET /api/skills/{name}
• memory API
  • GET /api/memory
• config APIs
  • GET /api/config
  • PATCH /api/config

Also included:

• session/message serialization helpers
• model override support for API-server-created agents
• SSE event translation for session chat streams

Why

Hermes Workspace can already use upstream in portable mode through:

• /health
• /v1/models
• /v1/chat/completions

But it needs additional Hermes-native APIs to unlock enhanced mode features like:

• persistent sessions
• enhanced session chat
• skills browsing
• memory inspection
• config editing

This PR adds those APIs by reusing existing upstream components (SessionDB, tools.skills_tool, hermes_cli.config, and AIAgent streaming callbacks) instead of introducing a parallel persistence layer.

Validation

Validated against a live Hermes deployment:

• /api/sessions works
• /api/skills works
• /api/memory works
• /api/config works

Hermes Workspace capability probing switched from portable mode to enhanced mode:

• sessions: true
• enhancedChat: true
• skills: true
• memory: true
• config: true
• jobs: true

Notes

• /api/memory is intentionally lightweight in this pass
• this PR does not add skill install/uninstall APIs
• existing API_SERVER_KEY auth behavior is unchanged

[alt-glitch]

Appears to overlap with #7866 and #6334 — both add workspace API endpoints to api_server. Please check if this supersedes or conflicts with those PRs.

[teknium1]

Thanks for the Workspace compatibility work. The session-control goal has since landed, but this patch needs a focused salvage rather than a direct merge.

Problems

• gateway/platforms/api_server.py:1349 persists caller-provided session IDs without the traversal/control-character/length validation current main applies at gateway/platforms/api_server.py:1737-1743; this boundary was hardened in ea1372d2.
• _serialize_session at gateway/platforms/api_server.py:470-474 returns full session rows, including system_prompt and parsed model_config. Current main intentionally uses a safe allowlist at gateway/platforms/api_server.py:1639-1654.
• PATCH /api/config at gateway/platforms/api_server.py:1835-1844 mutates arbitrary config and .env entries, while current /v1/capabilities explicitly advertises admin_config_rw: false (gateway/platforms/api_server.py:1502).
• The PR changes only api_server.py; no regression tests accompany the new HTTP surface.

Suggested changes

• Build any remaining Workspace-specific contract on the shipped session API (f7527b0fd) and current /v1/skills capability surface.
• Preserve the current session-ID validation and response redaction, and split administrative config/environment changes into an explicitly approved design with E2E coverage.

Automated hermes-sweeper review.

[teknium1]

This accepts arbitrary session IDs before persisting them. Current main rejects traversal/control-character/oversized IDs at this API boundary (gateway/platforms/api_server.py:1737-1743), added by security fix ea1372d2; carry that validation here before create_session.

[teknium1]

Returning a copied full SessionDB row exposes fields that the current API deliberately withholds, including system_prompt and model_config. Reuse a safe-field serializer like current main's _session_response instead of returning the full record.

[teknium1]

This turns the API-server bearer credential into unrestricted config and .env administration. Current main intentionally advertises admin_config_rw: false; please split this behind an explicitly designed administrative contract rather than including it in the session compatibility surface.