T02 typography: text styles, keys, formatters, fit, links, math, motion text

Headings to overlines, Code, Kbd and KbdCombo on gpui keystrokes,
Highlight, MiddleEllipsis and EllipsisTooltip, links, eight formatted
values on jiff with a typographic minus, CopyableText, SelectableText,
Emoji, a TeX subset, rolling AnimatedNumber, Typewriter, tonal
GradientText, ShimmerText. Gallery probes now hug their targets.
Codex gpt-6-astra (max): PASS in round 2.

Cargo.toml

@@ -14,10 +14,14 @@ runtime_shaders = ["gpui/runtime_shaders"]
 
 [dependencies]
 anyhow = "1"
+emojis = "0.9"
 gpui = "0.2.2"
+jiff = "0.2"
 log = "0.4"
+regex = "1"
 rust-embed = "8.12"
 smallvec = "1"
+unicode-segmentation = "1"
 
 [dev-dependencies]
 env_logger = "0.11"