sled-agent: gate RoT attestation endpoints on sled-local clients

[luqmana]

Added some checks to ensure the attestation endpoints may only be called from clients (propolis zones) on the same sled.

Using the switch zone as a stand-in, here's what that looks like to callers:

Same Sled:

# Switch Zone 1 -> Sled Agent (Cubby 16):
root@oxz_switch1:~# /tmp/verifier-cli --interface sled-agent --sled-addr '[fd2e:afd:d190:102::1]:12345' log                                                                                               
{"index":1,"measurements":[{"Sha3_256":[73,44,2,60,18,23,151,170,58,164,156,168,236,55,243,95,194,173,188,252,163,255,12,72,66,82,99,116,126,220,202,88]},{"Sha3_256":[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]},{"Sha3_256":[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]},{"Sha3_256":[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]},{"Sha3_256":[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]},{"Sha3_256":[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]},{"Sha3_256":[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]},{"Sha3_256":[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]},{"Sha3_256":[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]},{"Sha3_256":[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]},{"Sha3_256":[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]},{"Sha3_256":[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]},{"Sha3_256":[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]},{"Sha3_256":[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]},{"Sha3_256":[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]},{"Sha3_256":[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]}]}

00:47:48.318Z INFO SledAgent (dropshot (SledAgent)): accepted connection
    file = /home/luqman/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/dropshot-0.16.7/src/server.rs:1025
    local_addr = [fd2e:afd:d190:102::1]:12345
    remote_addr = [fd2e:afd:d190:102::2]:43892
00:47:48.380Z INFO SledAgent (dropshot (SledAgent)): request completed
    file = /home/luqman/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/dropshot-0.16.7/src/server.rs:867
    latency_us = 61982
    local_addr = [fd2e:afd:d190:102::1]:12345
    method = GET
    remote_addr = [fd2e:afd:d190:102::2]:43892
    req_id = e397b94f-3777-4e8a-bb9d-c7343efc1a13
    response_code = 200
    uri = /rot/oxide/measurement-log

Cross Sled:

# Switch Zone 1 -> Sled Agent (Cubby 15):
root@oxz_switch1:~# /tmp/verifier-cli --interface sled-agent --sled-addr '[fd2e:afd:d190:103::1]:12345' log                                                                                               
Error: Getting attestation measurement log

Caused by:
    Error Response: status: 400 Bad Request; headers: {"content-type": "application/json", "x-request-id": "fbd55e68-c00b-4604-bbe1-250c3b53d322", "content-length": "109", "date": "Thu, 12 Mar 2026 00:48:30 GMT"}; value: Error { error_code: None, message: "non-sled-local request not allowed", request_id: "fbd55e68-c00b-4604-bbe1-250c3b53d322" }

00:48:30.227Z INFO SledAgent (dropshot (SledAgent)): accepted connection
    file = /home/luqman/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/dropshot-0.16.7/src/server.rs:1025
    local_addr = [fd2e:afd:d190:103::1]:12345
    remote_addr = [fd2e:afd:d190:102::2]:46577
00:48:30.229Z INFO SledAgent (dropshot (SledAgent)): request completed
    error_message_external = non-sled-local request not allowed
    error_message_internal = non-sled-local request not allowed
    file = /home/luqman/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/dropshot-0.16.7/src/server.rs:855
    latency_us = 1250
    local_addr = [fd2e:afd:d190:103::1]:12345
    method = GET
    remote_addr = [fd2e:afd:d190:102::2]:46577
    req_id = fbd55e68-c00b-4604-bbe1-250c3b53d322
    response_code = 400
    uri = /rot/oxide/measurement-log