chore: post-merge redesign fixups

[arnautov-anton]

🎯 Goal

• adjust message reactions positioning (use justify-self instead)
• add reactions host offset for top-based positions
• move thread reply buttons to the message inner for proper bottom-based message reactions positioning

[github-actions]

Size Change: +70 B (+0.02%)

Total Size: 328 kB

Filename	Size	Change
./dist/cjs/index.js	195 kB	+3 B (0%)
./dist/css/index.css	27.4 kB	+67 B (+0.24%)

ℹ️ View Unchanged

Filename	Size
./dist/audioProcessing-BbOs2wMd.js	1.32 kB
./dist/Channel-C2U9Avwy.js	21.8 kB
./dist/ChannelPreview-7e6MlsFZ.js	7.11 kB
./dist/cjs/emojis.js	2.97 kB
./dist/cjs/experimental.js	3.62 kB
./dist/cjs/mp3-encoder.js	1.27 kB
./dist/css/emojis.css	113 B
./dist/css/v2/emoji-mart.css	1.84 kB
./dist/css/v2/emoji-replacement.css	300 B
./dist/css/v2/index.css	39.4 kB
./dist/css/v2/index.layout.css	22.8 kB
./dist/limits-ClmQ1xgC.js	3.39 kB

_{compressed-size-action}