[🔌 Provider]: Teamcity

[ilya-bogin-playrix]

Is your feature request related to a problem? Please describe.
Support Teamcity as a data source

Describe the solution you'd like
We want to get data directly from Teamcity

Describe alternatives you've considered
We can take the info from Grafana

Additional context
Add any other context or screenshots about the feature request here.

[talboren]

Thank you, @ilya-bogin-playrix!

[chengyixu]

/attempt #4444

PR submitted: #6170

Implements TeamCity pull mode (failed/cancelled builds from REST API) and webhook push mode (Tcwebhooks plugin or custom curl build step). 96 unit tests covering auth, status/severity mapping, timestamp parsing (TeamCity compact format), and pull mode.