fix: prompt for category before secondhand options

[seanwessmith]

What

• show an Add a category action in the Secondhand card when a product has no categories
• keep Donation and Used product options hidden until a category is available
• cover missing, empty, and populated categories_tags paths with a regression test

Why

Donation and Used product links need a category to build a relevant search. The action explains why those options are unavailable and takes contributors directly to the Categories field.

Validation

• make test-unit test=secondhand_knowledge_panels.t
• make check_perltidy TO_CHECK='lib/ProductOpener/KnowledgePanels.pm tests/unit/secondhand_knowledge_panels.t'
• make check_critic TO_CHECK='lib/ProductOpener/KnowledgePanels.pm tests/unit/secondhand_knowledge_panels.t'
• make check_translations
• git diff --check

Fixes #11110

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 55.50%. Comparing base (aa9ec3a) to head (ac2ad2e).
⚠️ Report is 5 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #14288      +/-   ##
==========================================
+ Coverage   50.28%   55.50%   +5.22%     
==========================================
  Files         103      104       +1     
  Lines       26414    26477      +63     
  Branches     6319     6330      +11     
==========================================
+ Hits        13282    14696    +1414     
+ Misses      11371     9854    -1517     
- Partials     1761     1927     +166     

Flag	Coverage Δ
integration-test-group-1	13.08% <0.00%> (?)
integration-test-group-2	9.20% <0.00%> (?)
integration-test-group-3	9.37% <0.00%> (?)
integration-test-group-4	33.39% <0.00%> (?)
integration-test-group-5	28.75% <0.00%> (?)
integration-test-group-6	9.14% <0.00%> (?)
integration-test-group-7	9.62% <0.00%> (?)
integration-test-group-8	28.29% <0.00%> (?)
integration-test-group-9	26.62% <0.00%> (?)
unit-test-group-1	25.78% <0.00%> (+0.77%)	⬆️
unit-test-group-2	31.03% <0.00%> (-0.23%)	⬇️
unit-test-group-3	34.40% <0.00%> (+0.83%)	⬆️
unit-test-group-4	22.43% <100.00%> (+0.14%)	⬆️
unit-test-group-5	27.74% <0.00%> (-0.56%)	⬇️
unit-test-group-6	22.06% <0.00%> (+0.55%)	⬆️

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

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

🚀 New features to boost your workflow:

• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[teolemon]

@seanwessmith the extra mile would be to add a nudge to add a category to get 2nd hand options. Something like "Add a category to discover 2nd hand options", using the Knowledge Panel Actions syntax present in other panels.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud