fix: activate healthchecks for HAProxy backends

[jansdhillon]

https://warthogs.atlassian.net/browse/LNDENG-4768

Health checks were being ignored for most backends because interval, rise, and fall were not set, so HAProxy can't correctly detect when the services are up. The haproxy-route library only activates health checks when all three are provided:

if interval and rise and fall:
    server_healthcheck_configuration = {
        "interval": interval,
        "rise": rise,
        "fall": fall,
        "path": path,
        "port": port,
    }

This PR adds check_interval=2, check_rise=2, check_fall=3 to all backends that were missing them, and keeps check_path set to the path each service actually serves (e.g. /ping for pingserver, /message-system for message-server).

Manual testing

make deploy

After the services start, set the HAProxy unit IP to landscape.local in /etc/hosts. Then verify all routes are healthy:

# appserver
http --verify=no -h get https://landscape.local/ | grep HTTP/ | cut -d ' ' -f 2
# api
http --verify=no -h get https://landscape.local/api/about | grep HTTP/ | cut -d ' ' -f 2
# pingserver
http --verify=no -h get http://landscape.local/ping | grep HTTP/ | cut -d ' ' -f 2
# msgserver
http --verify=no -h get https://landscape.local/message-system | grep HTTP/ | cut -d ' ' -f 2
# pkg upload
http --verify=no -h get https://landscape.local/upload | grep HTTP/ | cut -d ' ' -f 2

...

200
200
200
200
200

[Copilot]

Pull request overview

This PR ensures HAProxy health checks are actually enabled for Landscape’s routed backends by providing the full health-check timing tuple (check_interval, check_rise, check_fall) everywhere it was missing, and by aligning check_path values with real service endpoints (notably updating API to use /api/about).

Changes:

• Add check_interval=2, check_rise=2, check_fall=3 to the appserver, pingserver, message-server, and API HAProxy routes.
• Normalize package-upload health-check interval to 2 (seconds) and remove the repository route’s unused health-check path.
• Expand unit tests to assert per-route check_path and health-check timing, and to ensure check_port is not set.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/charm.py	Enables HAProxy health checks for key backends by supplying interval/rise/fall and updates API check path to /api/about; removes repository’s unused check path.
tests/unit/test_haproxy_route.py	Updates interval unit expectation (seconds) and adds coverage for per-route check paths and health-check timing configuration.

[HJK-X]

LGTM