REST API initial

[strijar]

Embedded REST API server for rnsd-rs.

Activated via --features api during build and the api_listen key in the [reticulum] section of the config, for example:

[reticulum]
api_listen = 127.0.0.1:8080

The server runs inside the rnsd process and accesses the transport directly via transport_tx, bypassing the pickle/HMAC protocol.

Routes

GET /health                     — liveness probe
GET /api/v1/status              — summary: counters + interface list
GET /api/v1/interfaces          — list of interfaces (?filter=…&all=true)
GET /api/v1/interfaces/{id}     — one interface by numeric id
GET /api/v1/paths               — path table (?max_hops=N)
GET /api/v1/links               — number of active links
POST /api/v1/interfaces         — add an interface
PUT /api/v1/interfaces/{id}     — replace the interface configuration
DELETE /api/v1/interfaces/{id}  — delete an interface