Azure DevOps On-Premises Support

[Tugrulhankars]

Summary

This PR introduces full support for Azure DevOps On-Premises (Server) in the azuredevops_go plugin, allowing enterprise users with self-hosted Azure DevOps instances to ingest DevOps data and compute DORA metrics.

Key Changes:

1. Connection & Auth Model (backend/plugins/azuredevops_go/models/connection.go):
   • Added Endpoint and Username fields to support custom On-Premises base URLs and HTTP Basic Authentication.
   • Updated base URL normalization to handle custom domains/IPs with subpaths (e.g. http://<IP>/DefaultCollection).
2. Database Migration (backend/plugins/azuredevops_go/models/migrationscripts/):
   • Added migration script 20260726_add_username_to_azuredevops.go to add username and endpoint columns to tool_azuredevops_go_connections.
3. GitExtractor IIS NTLM Auth Fix (backend/plugins/gitextractor/parser/clone_gitcli.go):
   • Injected -c http.extraHeader="Authorization: Basic <base64>" during git clone execution. This transmits the Basic Auth header on the initial request, bypassing IIS 401 NTLM challenges on Azure DevOps Server when authenticating via PATs.
   • Abstracted DiffLine model to remove non-CGO libgit2 build dependencies on Windows environments.
4. Config-UI (config-ui/src/plugins/register/azure/config.tsx & utils/request.ts):
   • Exposed Endpoint and Username fields in the Azure DevOps Go connection form.
   • Fixed false-positive login redirects when remote scope connection tests return HTTP 401.

Does this close any open issues?

Closes 8985

Screenshots

Include any relevant screenshots here.

Other Information

• Backward Compatibility: 100% backward compatible with existing Azure DevOps Cloud (dev.azure.com) connections.
• Tested: Tested and verified with live Azure DevOps Server (On-Premises) instance for data collection and Grafana DORA metric calculation.