OPS-157454: Upload test coverage to Codacy from CI

[davidnmbond]

Adds a coverage job to CI that collects test coverage and uploads it to Codacy.

• The test project runs as a Microsoft.Testing.Platform executable (UseMicrosoftTestingPlatformRunner) with Microsoft.Testing.Extensions.CodeCoverage, writing a Cobertura report.
• coverage.config ports the generated-code exclusions used across the estate, so figures stay comparable.
• The report is uploaded with codacy/codacy-coverage-reporter-action using the CODACY_PROJECT_TOKEN secret (continue-on-error, so a Codacy outage cannot turn a passing run red), and kept as a 7-day artifact.
• Runs on the self-hosted pdl-public runners, not a GitHub-hosted runner.

Excluded tests: none - every test is offline (132 tests, 1 explicitly skipped).

CI runs only tests that need no credentials. Tests are selected by what passes in a clean Linux container with no user secrets, exactly as CI sees it.

Local line coverage: 73.2%

Jira: https://jira.panoramicdata.com/browse/OPS-157454

🤖 Generated with Claude Code

[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

Results:
0 new issues

View in Codacy

🟢 Coverage ∅ diff coverage

Metric	Results
Coverage variation	Report missing for 8420f431
Diff coverage	✅ ∅ diff coverage

View coverage diff in Codacy

Coverage variation details

	Coverable lines	Covered lines	Coverage
Common ancestor commit (8420f43)	Report Missing	Report Missing	Report Missing
Head commit (83ef29e)	2198	1609	73.20%

Coverage variation is the difference between the coverage for the head and common ancestor commits of the pull request branch: <coverage of head commit> - <coverage of common ancestor commit>

Diff coverage details

	Coverable lines	Covered lines	Diff coverage
Pull request (#24)	0	0	∅ (not applicable)

Diff coverage is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified: <covered lines added or modified>/<coverable lines added or modified> * 100%

¹ Codacy didn't receive coverage data for the commit, or there was an error processing the received data. Check your integration for errors and validate that your coverage setup is correct.

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_{TIP This summary will be updated as you push new changes.}