Visor: grapheme-aware glyph input and emoji picker

[lannbot]

Summary

• Replace scalar-value truncation with unicode-segmentation: strip leading Unicode whitespace and retain the first extended grapheme, without NFC normalization.
• Reuse one glyph input for user and app labels, supporting typing, paste, IME composition, and a searchable in-page emoji picker.
• Bundle the emoji catalogue locally through emojis, including skin-tone variants and paged results. No third-party runtime requests or JavaScript picker state.
• Preserve compound glyphs in saved metadata display, strip rendering, and launcher icon painting. Existing metadata is normalized for display without an automatic storage migration.

Verification

• Astra review complete; desktop/mobile Chromium screenshots inspected.
• just check, just test, and just e2e passed; all 29 Chromium scenarios pass.
• Coverage includes whitespace, combining marks, ZWJ sequences, skin tones, flags, keycaps, variation selectors, same-value paste normalization without focus loss, composition commit, picker search/selection/Escape, Save/Revert/reload, and launcher canvas input.
• Current visor component is 379,168 bytes gzipped; raw size grows by approximately 417KB from the bundled catalogue and picker.

Automerge will be armed.