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.

scripts/check.sh

@@ -0,0 +1,17 @@
+#!/bin/sh
+# Pre-review gate: build rules plus house rules.
+set -eu
+cargo fmt --check
+cargo clippy --all-targets -- -D warnings
+cargo test --lib --quiet
+fail=0
+files=$(git ls-files -co --exclude-standard '*.rs')
+multi=$(awk 'FNR==1{prev=0} /^[[:space:]]*\/\// {if(prev) print FILENAME":"FNR; prev=1; next} {prev=0}' $files)
+[ -z "$multi" ] || { echo "multi-line comments:"; echo "$multi"; fail=1; }
+for f in $files AGENTS.md README.md TASKS.md tasks/*.md; do
+  n=$(wc -l < "$f")
+  [ "$n" -le 500 ] || { echo "$f has $n lines"; fail=1; }
+done
+raw=$(grep -rnE "(^|[^.[:alnum:]_])px\(" src --include='*.rs' | grep -v "^src/theme/tokens.rs\|^src/motion/" || true)
+[ -z "$raw" ] || { echo "raw px in components:"; echo "$raw"; fail=1; }
+exit $fail