feat(quality): OpenAPI spec path coverage across both transports

[vriesdemichael]

Summary

Adds an automated OpenAPI spec path coverage report so unimplemented API surface is visible and tracked in CI.

The existing generated_contracts metric only counts generated-client calls of the form x.client.OpWithResponse(...). It is blind to services built on the raw internal/transport/httpclient — most notably the entire pullrequest service — so it under-reports real API coverage (it implies PR endpoints are ~0% covered when create/merge/decline/reopen/approve/auto-merge/participants are all implemented).

What this does

A new standalone -spec-coverage mode in tools/quality-report measures coverage at the (HTTP method, path) level, joining the Bitbucket 9.4 OpenAPI spec against operations reached through both transports:

1. The generated typed client (internal/openapi/generated), restricted to the operations actually called from internal/services.
2. The hand-rolled httpclient (GetJSON/PostJSON/...), with request paths resolved statically from the services source — handling string literals, fmt.Sprintf assembly, single-return path helpers, local path variables, and parameter-literal substitution (so the shared transition("merge"|"decline"|"reopen") helper resolves to its real endpoints).

Resolution is undercount-safe: unresolvable dynamic segments collapse to a non-matching placeholder rather than wildcard-matching, so the number is a floor, never inflated.

Deliverables

• docs/quality/spec-coverage.json — committed, deterministic artifact: 112/546 (20.5%) with per-tag breakdown and the full list of unimplemented gaps (method, path, tag, summary). Does not depend on coverage profiles or live tests.
• Task targets: quality:spec-coverage, quality:spec-coverage:update, quality:spec-coverage:verify.
• CI: artifact verification wired into the CI-safe unit-tests job.
• Unit tests for normalization, verb substitution, raw-path resolution (incl. parameter substitution), and generated-client WithBody parsing.
• Docs: docs/quality/README.md and AGENTS.md updated with the regeneration workflow.

Verification

• go test ./tools/quality-report/ — passing; gofmt/go vet clean.
• Artifact round-trips: task quality:spec-coverage:verify passes against the committed file.
• Spot-checked classification: raw PR endpoints (create/merge/decline/reopen/approve/auto-merge/assign-participant) count as covered; genuine gaps (delete PR, change participant status, merge-base, search participants) remain listed.

Resolves #208

https://claude.ai/code/session_012Ax4aEmr2XgmGi52Grzhk3

---

Generated by Claude Code

[codecov-commenter]

Codecov Report

❌ Patch coverage is 55.16304% with 165 lines in your changes missing coverage. Please review.
✅ Project coverage is 83.31%. Comparing base (c213f55) to head (6fad3d1).

Files with missing lines	Patch %	Lines
tools/quality-report/speccoverage.go	56.38%	139 Missing and 18 partials ⚠️
tools/quality-report/main.go	0.00%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #222      +/-   ##
==========================================
- Coverage   83.90%   83.31%   -0.60%     
==========================================
  Files          80       81       +1     
  Lines       16624    17000     +376     
==========================================
+ Hits        13949    14164     +215     
- Misses       1933     2080     +147     
- Partials      742      756      +14     

Flag	Coverage Δ
combined_scoped	83.31% <55.16%> (-0.60%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.