Authentication - TraceLM

1. Proxy Calls (`/v1/...`)

For POST /v1/chat/completions and POST /v1/completions:

X-API-Key: lt_... (TraceLM project key)
Authorization: Bearer <provider_key>
Optional X-Provider: openai | anthropic | google (defaults to openai)

curl -X POST "https://api.tracelm.ai/v1/chat/completions" \
  -H "X-API-Key: $TRACELM_API_KEY" \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -H "X-Provider: openai" \
  -H "Content-Type: application/json" \
  -d '{"model":"gpt-4o-mini","messages":[{"role":"user","content":"Hello"}]}'

2. Product APIs (`/api/v1/...`)

Most management/reporting endpoints use JWT auth:

Authorization: Bearer <access_token>

Some task/conversation endpoints accept either JWT or X-API-Key.

Agent Context Headers (Optional)

Send these on proxy requests for execution grouping:

X-Task-ID
X-Task-Name
X-Conversation-ID
X-User-ID

These headers drive timeline assembly, loop/failure/context detection, and conversation grouping.