feat(categories): add custom category management (#48)

[dextro172-ui]

Pull Request Checklist

Quality Gates (All must pass before merge)

• Lint: Code passes ESLint and Prettier checks
• Type Check: TypeScript compilation succeeds
• Tests: All tests pass
• Build: Project builds successfully
• Rust Format: Smart contract formatting is correct
• Rust Clippy: Smart contract linting passes
• Rust Tests: All smart contract tests pass
• Rust Build: Smart contracts compile successfully

Additional Requirements

• New code has appropriate TypeScript types
• No hardcoded secrets or credentials
• New features have corresponding tests
• Documentation updated if needed

Reviewers

• At least 1 approval required for merge
• All CI checks must be green

---

This PR will not be mergeable until all quality gates pass.

---

Summary

Implements full custom category management for SubTrackr, allowing users to create, edit, and delete their own subscription categories while preserving the built-in defaults.

Related Issue

Closes #48

Changes Made

New Files

File	Purpose
src/utils/constants/categories.ts	Default category definitions, 20-color palette, 28 icon options, max limit constant
src/store/categoryStore.ts	Zustand store with CRUD, validation, persistence, guards
src/components/CategorySelector.tsx	Reusable picker with inline create/edit/delete modals
src/components/CategoryBadge.tsx	Visual badge with color dot and category name
src/components/CategoryPieChart.tsx	Analytics pie chart using category colors
src/screens/CategoryManagementScreen.tsx	Full-screen management with FAB, cards, modals
src/components/index.ts	Barrel export for new components
src/screens/index.ts	Barrel export for new screens

Modified Files

File	Change
src/types/subscription.ts	Added CustomCategory, CustomCategoryFormData, CategoryValue types
src/store/subscriptionStore.ts	Added reassignCategory() action for bulk category reassignment

Acceptance Criteria

• User can create new category (name, icon, color)
• Custom categories appear in selector alongside defaults
• Categories can be edited (name, icon, color)
• Categories can be deleted (with guardrails)
• Default categories remain immutable
• Maximum 20 custom categories enforced
• Cannot delete category with active subscriptions (with reassign option)
• Icon and color selection UI included

Technical Notes

• Uses Zustand + zustand/middleware persist for offline-first storage
• Duplicate name validation (case-insensitive) across all categories
• reassignCategory() updates all subscriptions atomically and recalculates stats
• Category data stored separately from subscriptions (subtrackr-categories key)
• Full TypeScript typing with no any usage
• All new code follows existing project patterns (errorHandler, debounced storage, etc.)

Testing Notes

• Unit tests for categoryStore actions (add, update, delete, validation)
• Integration tests for category CRUD flow
• Verify stats recalculation after reassignCategory
• Test max category limit edge case
• Test duplicate name rejection
• Test default category immutability

[drips-wave]

@dextro172-ui Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

Learn more about application limits

[Smartdevs17]

⚠️ Merge failed — check CI status.

🤖 Drips Wave Merge Agent