Add Go code coverage reporting with Cobertura XML and GitHub upload

[code-coverage-agent]

Adds Go code coverage reporting integrated into the existing CI pipeline, producing Cobertura XML reports and uploading them to GitHub's code coverage API for PR annotations and baseline comparisons.

Changes

Makefile

• Defines GOCOVER_COBERTURA pointing to $(TOOLS_HOST_DIR)/gocover-cobertura
• Adds auto-install target for gocover-cobertura via go install
• Wires the existing cobertura target to depend on the tool, so make cobertura is self-contained

.gitignore

• Excludes _output/tests/ (coverage profiles, Cobertura XML, test logs)

.github/workflows/ci.yml

• Adds make cobertura step in unit-tests job to convert coverage.txt → cobertura-coverage.xml, filtering out generated (zz_*) files
• Uploads the Cobertura XML as a workflow artifact (skipped on fork PRs)
• Adds upload-coverage-go job with code-quality: write that downloads the artifact and calls actions/upload-code-coverage@v1; gated so it only runs when unit-tests succeeds and not on fork PRs

[github-code-quality]

Code Coverage Overview

Languages: Go

Go / code-coverage-agent

The overall coverage in commit 36a277c in the code-coverage-agent/... branch is 0%. Coverage data for the main branch is not yet available.

Show a code coverage summary of the most covered files.

File	main	code-coverage-agent/... 36a277c	+/-
apis/cluster/v1...ha1/register.go	—	0%	—
apis/cluster/v1...ta1/register.go	—	0%	—
apis/namespaced...ha1/register.go	—	0%	—
apis/namespaced...ta1/register.go	—	0%	—
cmd/generator/main.go	—	0%	—
cmd/provider/main.go	—	0%	—
internal/clients/scaleway.go	—	0%	—
internal/contro...onfig/config.go	—	0%	—
internal/contro...onfig/config.go	—	0%	—

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 0.00%. Comparing base (e882094) to head (36a277c).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #340   +/-   ##
=======================================
  Coverage    0.00%    0.00%           
=======================================
  Files        1233     1233           
  Lines      131470   131470           
=======================================
  Misses     131470   131470           

Flag	Coverage Δ
unittests	0.00% <ø> (ø)

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