feat: introduce extended reaction list to a reactions detail component

[arnautov-anton]

https://www.figma.com/design/Us73erK1xFNcB5EH3hyq6Y/Chat-SDK-Design-System?node-id=4305-171859&m=dev

New ComponentContext slot: ReactionSelectorExtendedList

A new optional component override has been added to ComponentContextValue:

ReactionSelectorExtendedList?: React.ComponentType<
  ComponentProps<(typeof ReactionSelector)['ExtendedList']>
>;

This allows consumers to replace the extended reaction list UI (the grid of all available reactions) independently of the ReactionSelector component itself. Both ReactionSelector and MessageReactionsDetail now consume this slot from context, falling back to ReactionSelector.ExtendedList when not provided. Pass it via <Channel ReactionSelectorExtendedList={YourComponent} />.

Bug fix: reactionDetailsSort prop now forwarded to MessageReactionsDetail

The reactionDetailsSort prop on MessageReactions was accepted but silently ignored (the destructured value was unused, suppressed with an eslint-disable comment). It is now correctly forwarded to the MessageReactionsDetail child component, meaning custom sort orders for the reaction detail user list will take effect.

New i18n key: "Add reaction"

A new translatable string "Add reaction" has been added to all 12 locale files. It is used as the aria-label on the "add reaction" button inside MessageReactionsDetail. Custom translation bundles should include this key.

Styling changes

Three CSS changes in MessageReactionsDetail.scss:

1. Fade overlay height increased from var(--size-12) to var(--size-16).
2. Fade overlay gradient changed from a hardcoded rgba(0,0,0,0.1) to var(--background-core-elevation-0), making it theme-aware.
3. Reaction type list horizontal padding changed from var(--spacing-xs) to var(--spacing-md).

Consumers who override these styles with selectors targeting .str-chat__message-reactions-detail descendants may need to adjust.

[github-actions]

Size Change: +1.99 kB (+0.32%)

Total Size: 617 kB

📦 View Changed

Filename	Size	Change
dist/cjs/emojis.js	2.96 kB	+1 B (+0.03%)
dist/cjs/index.js	237 kB	+638 B (+0.27%)
dist/cjs/WithAudioPlayback.js	44 kB	+302 B (+0.69%)
dist/css/index.css	45.5 kB	+127 B (+0.28%)
dist/es/emojis.mjs	2.47 kB	-2 B (-0.08%)
dist/es/index.mjs	236 kB	+633 B (+0.27%)
dist/es/WithAudioPlayback.mjs	43.8 kB	+293 B (+0.67%)

ℹ️ View Unchanged

Filename	Size
dist/cjs/audioProcessing.js	1.32 kB
dist/cjs/mp3-encoder.js	1.27 kB
dist/css/emoji-replacement.css	456 B
dist/es/audioProcessing.mjs	1.31 kB
dist/es/mp3-encoder.mjs	756 B

_{compressed-size-action}

[codecov]

Codecov Report

❌ Patch coverage is 83.33333% with 13 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.26%. Comparing base (443b9a8) to head (45eda82).

Files with missing lines	Patch %	Lines
...rc/components/Reactions/MessageReactionsDetail.tsx	64.70%	12 Missing ⚠️
src/components/Reactions/ReactionSelector.tsx	96.29%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3100      +/-   ##
==========================================
+ Coverage   82.21%   82.26%   +0.05%     
==========================================
  Files         418      418              
  Lines       12044    12074      +30     
  Branches     3875     3882       +7     
==========================================
+ Hits         9902     9933      +31     
+ Misses       2142     2141       -1     

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