chore: doc, lint, test

[fredbi]

chore: updated dependencies (suppress mongodb dependency)

doc: aligned documentation with other go-openapi repos
doc: relinted godoc
doc: relinted markdown
doc: added instructions for coding agents (claude, copilot)

test: adopted testify/v2's generics
test: simplified tests using new json assertions
test: simplified tests using embedded fixtures

Change type

Please select: 🆕 New feature or enhancement|🔧 Bug fix'|📃 Documentation update

Short description

Fixes

Full description

Checklist

• I have signed all my commits with my name and email (see DCO. This does not require a PGP-signed commit
• I have rebased and squashed my work, so only one commit remains
• I have added tests to cover my changes.
• I have properly enriched go doc comments in code.
• I have properly documented any breaking change.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.78%. Comparing base (fa44b87) to head (ebcbc26).
⚠️ Report is 11 commits behind head on master.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #125   +/-   ##
=======================================
  Coverage   80.78%   80.78%           
=======================================
  Files           4        4           
  Lines         229      229           
=======================================
  Hits          185      185           
  Misses         28       28           
  Partials       16       16           

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