refactor(ui): extend typography/line-height converge contracts to TSX (#546 PR0)

[Astro-Han]

Summary

Extends the typography/line-height converge contracts to scan .tsx (not just CSS), closing the CSS-only blind spot from #520, and converges ~64 arbitrary text-[..]/leading-[..] Tailwind utilities onto the token scale. First PR of the #546 CSS governance pass.

Why

#520's converge contracts locked every numeric spec in renderer CSS, but they only scanned .css — arbitrary text-[12px] / leading-[1.45] utilities living in .tsx className strings were a complete blind spot (~64 sites across 6 files). #546 PR0 closes that gap so TSX is governed by the same token discipline as CSS.

Refs #546

Scope

Changed:

• css-test-helpers.ts: add readRendererTsxFiles()
• typography-converge + line-height-converge contracts: new TSX-scanning test (regex covers numeric arbitrary, length:calc(..), and text-*/[<num>] slash line-height modifier; var/color refs, named scales, and leading-[Npx] icon-centering stay allowed) + negative cases
• 5 source files converged (primitives/chat.tsx, tool-activity.tsx, primitives/badge.tsx, chat-view.tsx, attachment-file-card.tsx): ≤12.5px→text-xs, 13px→text-sm; leading 1.4/1.45→snug, 1.5/1.6→normal
• 4 feat(ui): govern chat conversation-flow display onto @maka/ui Base UI primitives #332 chat migration contracts updated (3 desktop cascade + @maka/ui chat-primitives): their typography anti-drift pinned arbitrary literals and banned text-xs/sm; refactor(ui): close out post-#520 renderer surface polish #546 PR0 intentionally converges typography onto the scale, so typography literals are unpinned and text-xs/sm allowed — radius/spacing anti-drift preserved

Not included:

• markdown prose layer / bubble extraction (later surface-polish PR)
• surface relocation (Phase A)
• full tool-cva extraction (separate decision)

Verification

• npm run typecheck — green (all workspaces)
• npm run -w @maka/desktop test — 2135/2136 pass
• npm test --workspace @maka/ui — 45/45 pass
• codex exec review --base origin/main — PASS (no P0/P1/P2/P3)
• The one desktop fail (history-compact-artifacts) is pre-existing — a runtime artifact-size classification unrelated to this diff (the test reads artifact block summaries, not renderer className)

User-facing impact

Near-zero visual shift: ≤1px font-size and ≤0.1 line-height deltas on tool-card meta/code/labels. No changelog/docs/migrations.

Reviewer notes

• The TSX scan covers literal className strings only — not clsx/cva maps, template strings, or inline style={{}} (stated honestly in the contract comments).
• leading-[12px]/[16px] on fixed-height icon buttons are deliberate px centering, kept (same exception refactor(ui): close out post-#520 renderer surface polish #546 recorded).
• Rollback: single revert; no token/schema/migration changes.

Checklist

• Scope matches the PR title and excludes unrelated changes
• Verification lists commands/results
• User-facing impact noted (near-zero)
• Risk/rollback called out
• UI screenshots — N/A (≤1px shifts on a governance PR; dual-theme screenshots land with the surface-polish PRs where pixels actually change)