Large single emoji looks oversized and blurry on Retina (3×) displays

[anriltine]

Steps to reproduce

1. On an iPhone with a Retina 2×/3× display, enable Settings → Stickers and Emoji → Large Emoji (or equivalent).
2. Send a message that contains exactly one Unicode emoji (no other text, no custom emoji).
3. Observe the large emoji in the chat.

Expected behaviour

The single large emoji should be sharp (pixel-aligned to Apple Color Emoji bitmap rungs) and similar in visual weight to other clients (Android TYPE_EMOJIS is ~41dp for a single standard emoji).

Actual behaviour

The emoji is rendered very large (~94pt via fontSizeForEmojiString) and looks soft/blurry on high-DPI screens because CoreText/Apple Color Emoji upsamples between discrete bitmap sizes.

Operating system

iOS (Retina / Super Retina), Telegram iOS

Notes

• Related: Large emoji render does not update correctly after editing emoji count on iOS #2139 (large emoji layout not refreshing after edit)
• Fix PR: (will link after create)

Android

Checked DrKLO/Telegram: large emoji uses density-scaled sprite bitmaps — not the same blur path.

[anriltine]

Fix PR

#2291

fontSizeForEmojiString used 94pt for a single emoji (≈2× Android’s ~41dp large-emoji path). On 2×/3× Retina, Apple Color Emoji bitmaps are upsampled between discrete rungs → soft/blurry.

Change: use Apple Color Emoji rung sizes (48/40/32/…) and set the large-emoji TextNode contentsScale to UIScreen.main.scale.

Related: #2139