Feature/add proxy support

[derrick-dacosta]

Testing results

docker compose.yml

services:
  redfish:
    image: dmtf/redfish-mockup-server:latest
    container_name: redfish
    command:
      - "-s"
      - "--cert=/server.crt"
      - "--key=/private.key"
    ports:
      - "8000:8000"
    restart: unless-stopped
    volumes:
      - ./private.key:/private.key
      - ./server.crt:/server.crt

  squid:
    image: ubuntu/squid:latest
    container_name: squid_proxy
    ports:
      - "3128:3128"
    restart: unless-stopped
    volumes:
      - ./squid.conf:/etc/squid/squid.conf:ro
    environment:
      - TZ=UTC

fishymetrics command

curl 'http://localhost:10023/scrape?target=https://redfish:8000&model=redfish-mockup&proxy_host=localhost:3128'

fishymetrics logs

% go run cmd/fishymetrics/*.go --insecure-skip-verify
{"level":"info","ts":"2025-09-11T10:36:18-04:00","caller":"fishymetrics/main.go:310","msg":"started fishymetrics service","app":"fishymetrics","host":"..."}
{"level":"info","ts":"2025-09-11T10:36:21-04:00","caller":"handlers/scrape.go:90","msg":"started scrape","app":"fishymetrics","host":"...","model":"redfish-mockup","target":"https://redfish:8000","credential_profile":"","trace_id":"ms4vcwzunuui7d1fbt1hyg4ivun49yqx"}
{"level":"info","ts":"2025-09-11T10:36:22-04:00","caller":"logging/logging.go:53","msg":"finished handling","app":"fishymetrics","host":"...","model":"redfish-mockup","target":"https://redfish:8000","sourceAddr":"127.0.0.1:52321","method":"GET","url":"/scrape?target=https://redfish:8000&model=redfish-mockup&proxy_host=localhost:3128","proto":"HTTP/1.1","status":200,"elapsed_time_sec":1.335071417,"trace_id":"ms4vcwzunuui7d1fbt1hyg4ivun49yqx"}

[ibrahimkk-moideen]

LGTM.

[ibrahimkk-moideen]

LGTM.