feat favorites infrastructure

[Mbeaulne]

Description

Added a new useFavorites React hook that provides functionality for managing user favorites in localStorage. The hook supports adding, removing, and toggling favorite items (pipelines and runs), with automatic synchronization across browser tabs using useSyncExternalStore. Includes comprehensive test coverage with 124 test cases covering all functionality including duplicate prevention, cross-tab synchronization, and type-specific item handling.

Related Issue and Pull requests

Type of Change

• Bug fix
• New feature
• Improvement
• Cleanup/Refactor
• Breaking change
• Documentation update

Checklist

• I have tested this does not break current pipelines / runs functionality
• I have tested the changes on staging

Screenshots (if applicable)

Test Instructions

1. Import and use the useFavorites hook in a React component
2. Test adding favorites using addFavorite(item)
3. Test removing favorites using removeFavorite(type, id)
4. Test toggling favorites using toggleFavorite(item)
5. Verify isFavorite(type, id) correctly identifies favorite status
6. Open multiple browser tabs to verify cross-tab synchronization works
7. Run the test suite to ensure all functionality passes

Additional Comments

The hook uses typed storage for persistence and implements caching to ensure stable references for useSyncExternalStore. It properly handles different item types (pipeline/run) with the same ID as separate entities.

[github-actions]

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[Mbeaulne]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• Add components section #2025
• Add dashboard home view with favorites, recently viewed, and my runs sections #2011
• moves app footer #2010
• add new section to the side bar #2004
• Updates runs and pipelines designs #2003
• Adds runs and filters #2002
• update favourite and recent cards #2001
• Updates revently viewed #2000
• Adds recently viewed #1999
• Update design for favourites #1998
• add favourites to new dashboard #1997
• feat dashboard latout #1996
• Feat recently viewed #1986
• feat_favorites_filter #1985
• feat_favorites_homepage_section #1983
• feat_favorites_toggle_ui #1982
• feat favorites infrastructure #1980 👈 (View in Graphite)
• Dashboard and beta #1932
• Add Claude AI skills for project conventions and development standards #1931
• master

This stack of pull requests is managed by Graphite. Learn more about stacking.

[Mbeaulne]

Reviewer note: Clean, stable PR. useFavorites.ts and its tests are the real foundation of the favorites feature and remain unchanged throughout the rest of the stack. Safe to review in isolation.