Feat/sms 46 bind UI and api to different addresses

[adhityaravi]

Issue

Fixes issue #56

Solution

1. A config option to define a dashboard address is added to the config yaml.
2. Depending on if the dashboard address config exists or not, cos-alerter is started in monolithic or microservice mode
3. No dashboard addr in config, single server that serves both api and dashboard
4. dashboard addr exists, dashboard served on dashboard addr and api server on web addr.

Context

Both the flask servers are started in the same process in different threads so the sate info is shared between them

Testing Instructions

1. Create test config (test-config.yaml) with the following contents

 watch:
    clients:
      test-client:
        key: "822295b207a0b73dd4690b60a03c55599346d44aef3da4cf28c3296eadb98b2647ae18863cc3ae8ae5574191b60360858982fd8a8d176c0edf646ce6eee24ef9"
        name: "Test Client"
  notify:
    destinations: []
  web_listen_addr: "127.0.0.1:8080"

2. Start server

  pip install -e .
  cos-alerter --config test-config.yaml &

3. Test both endpoints on same port

  curl http://127.0.0.1:8080/  # Should return dashboard HTML
  curl -X POST "http://127.0.0.1:8080/alive?clientid=test-client&key=clientkey1"  # Should return "Success!"

4. Test Microservice Mode (new feature)

  echo 'dashboard_listen_addr: "127.0.0.1:8081"' >> test-config.yaml

5. Restart server

  pkill -f cos-alerter
  cos-alerter --config test-config.yaml &

6. Test split endpoints

  curl http://127.0.0.1:8080/  # Should return 404 (API server only)
  curl -X POST "http://127.0.0.1:8080/alive?clientid=test-client&key=clientkey1"  # Should return "Success!"

  curl http://127.0.0.1:8081/  # Should return dashboard HTML
  curl -X POST "http://127.0.0.1:8081/alive?clientid=test-client&key=clientkey1"  # Should return 404 (dashboard server only)

[adhityaravi]

Ci fixes from #86 need to be merged into this PR for the checks to pass