✨ feat(cli): add --namespace / -N flag to data-access commands

[sodre]

Summary

• Add --namespace / -N flag to all 17 data-access CLI commands across entity, resource, system, audit, and usage groups
• When a non-default namespace is provided, scopes the repository via repo.namespace() before executing business logic
• Implements a namespace_option decorator and _resolve_namespace helper for DRY application across commands
• Default namespace ($default) is a no-op for backward compatibility

Test plan

• 11 unit tests covering each command group + short flag -N
• 100% diff coverage on changed lines
• All 2338 existing unit tests pass

Closes #368

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.86%. Comparing base (d808008) to head (8a98db7).
⚠️ Report is 2 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #383      +/-   ##
==========================================
+ Coverage   91.82%   91.86%   +0.04%     
==========================================
  Files          33       33              
  Lines        7385     7426      +41     
==========================================
+ Hits         6781     6822      +41     
  Misses        604      604              

Flag	Coverage Δ
doctest	26.98% <0.00%> (-0.15%)	⬇️
e2e	40.57% <61.90%> (-0.54%)	⬇️
integration	49.27% <85.71%> (+0.18%)	⬆️
unit	91.61% <100.00%> (+0.04%)	⬆️

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.