fix(budget): categories filter only applies to Budget Health, not Cost Breakdown

[steilerDev]

Summary

• Categories filter on the budget page now only filters the Budget Health section
• Cost Breakdown table always shows all categories regardless of filter selection
• Added stable emptyCategories constant to avoid re-renders

Fixes #577

Test plan

• 2 new tests verifying filter scope (Budget Health filtered, Cost Breakdown unfiltered)
• All 61 existing tests pass

Co-Authored-By: Claude Opus 4.6 noreply@anthropic.com

[steilerDev]

[security-engineer]

PR #578 reviewed. Frontend-only bug fix — 2 lines of production code changed:

1. Module-level const emptyCategories = new Set<string | null>() added (stable reference, no user input).
2. selectedCategories={emptyCategories} replaces selectedCategories={selectedCategories} at the CostBreakdownTable call site.

Security checklist:

• No injection surface — no user input, no API calls, no DOM manipulation
• No new dependencies
• No sensitive data exposure
• No auth/authz changes
• No XSS vectors — the emptyCategories constant is a typed Set literal; CostBreakdownTable was already audited (PR #157)
• Test additions correctly assert the intentional decoupling of the cost breakdown from the category filter state

No security findings.

[steilerDev]

[product-architect]

Reviewed the 2-file diff. Clean, minimal fix with correct approach.

Architecture compliance: Pass. No structural changes -- just a prop value swap at the page level.

Technical correctness:

• The module-level emptyCategories constant is the right pattern: stable reference avoids unnecessary re-renders of CostBreakdownTable, and size === 0 is already the "show all" semantic in that component (line 606).
• No risk of mutation since the Set is never exposed to modifying code.

Test coverage: Two new tests adequately cover the fix -- partial category selection and full clear -- verifying that Budget Health filters while Cost Breakdown remains unaffected.

No wiki updates needed (no API, schema, or architecture changes).

LGTM.

[github-actions]

🎉 This PR is included in version 1.13.0-beta.26 🎉

The release is available on GitHub release

Your semantic-release bot 📦🚀

[github-actions]

🎉 This PR is included in version 1.13.0 🎉

The release is available on GitHub release

Your semantic-release bot 📦🚀