REST endpoints

Stub. Endpoint list will firm up when the service comes online.

GET    /health                 # liveness
GET    /entities/{id}          # fetch one
POST   /entities               # create
PATCH  /entities/{id}          # update (audited)
DELETE /entities/{id}          # tombstone (audited)

GET    /edges?from=&to=&type=  # filter edges
POST   /edges                  # add edge (audited)
DELETE /edges/{id}             # remove edge (audited)

POST   /query                  # flexible graph traversal (Cypher-lite or JSON-DSL)
GET    /events                 # audit log (paginated)

All mutations require an authenticated agent token mapped to a graph entity. Responses are JSON. Errors use standard HTTP status codes.