perf(playground): narrow font range for loading states

[wiyco]

Summary

• Replace loading-state ellipses with ASCII periods and remove U+2026 from the Geist unicode ranges.
• Disable font ligatures in playground code surfaces so JSX spread syntax renders as {...props}.
• Document the typography rationale for keeping Geist in the stack while narrowing runtime glyph usage.

Tests

• pnpm vitest run apps/playground/src/design-token-sync.test.ts apps/playground/src/core/svg-playground/ui/SvgPlayground.test.tsx apps/playground/src/core/svg-playground/ui/SvgPlayground/panels/CodeSurface.test.tsx
• pnpm --filter ./apps/playground build
• pnpm run test:browser:playground -- src/playgrounds/svgo-plugin-hoist-stroke-width/App.browser.test.tsx

[github-actions]

Code Metrics Report

Download coverage report: lcov-report

	main (a7fb939)	#4 (f7e73e0)	+/-
Coverage	100.0%	100.0%	0.0%
Code to Test Ratio	1:1.8	1:1.8	+0.0
Test Execution Time	1s	1s	0s

Details

  |                     | main (a7fb939) | #4 (f7e73e0) | +/-  |
  |---------------------|----------------|--------------|------|
  | Coverage            |         100.0% |       100.0% | 0.0% |
  |   Files             |             63 |           63 |    0 |
  |   Lines             |           1323 |         1323 |    0 |
  |   Covered           |           1323 |         1323 |    0 |
+ | Code to Test Ratio  |          1:1.8 |        1:1.8 | +0.0 |
  |   Code              |           4261 |         4265 |   +4 |
+ |   Test              |           7939 |         7948 |   +9 |
  | Test Execution Time |             1s |           1s |   0s |

Code coverage of files in pull request scope (100.0% → 100.0%)

Files	Coverage	+/-	Status
apps/playground/src/core/svg-playground/ui/SvgPlayground/panels/CodeSurface.editor.tsx	100.0%	0.0%	modified
apps/playground/src/core/svg-playground/ui/SvgPlayground/panels/OptimizedPanel.tsx	100.0%	0.0%	modified
apps/playground/src/core/svg-playground/ui/SvgPlayground/panels/PreviewPanel.tsx	100.0%	0.0%	modified
apps/playground/src/core/svg-playground/ui/SvgPlayground/panels/ReactSourcePanel.tsx	100.0%	0.0%	modified
apps/playground/src/core/svg-playground/ui/SvgPlaygroundPage.tsx	100.0%	0.0%	modified

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Reported by octocov