refactor(theme): compress legacy color key aliases

[limityan]

Summary

• Retire explicit root/runtime compatibility aliases and keep legacy theme names out of internal product reads.
• Consolidate tool-card, button, window-control, semantic status, surface/text/border, primary/accent, danger, font, and motion reads onto canonical tokens.
• Shrink generated widget theme payload while preserving historical legacy color reads through iframe-only fallback aliases.
• Tighten theme color governance tests and baselines so retired aliases, dynamic family drift, undefined vars, and payload regressions are blocked.

Metrics

Metric	Before	After
explicit compatibility alias contracts	65	0
generated widget payload vars	176	157
theme preset color occurrences / unique	206 / 174	190 / 162
specialized near-color pairs	125	119
app raw color occurrences / unique	0 / 0	0 / 0

Risk Review

• Root/runtime legacy aliases are intentionally retired; generated widget historical content remains covered by iframe fallback aliases.
• Adjacent severity states stay distinguishable: high risk uses a warning/error mix instead of collapsing into medium warning.
• Dynamic radius/spacing family compatibility remains explicitly contracted and audited.
• External custom CSS that reads retired root/runtime aliases should migrate to canonical tokens.

Verification

• pnpm run theme:color-audit -- --top 30
• node --test scripts/audit-theme-colors.test.mjs
• pnpm --dir src/web-ui run test:run src/tools/generative-widget/themePayload.test.ts src/infrastructure/theme/core/ThemeService.test.ts src/infrastructure/theme/presets/themePresetOutput.test.ts
• pnpm run lint:web
• pnpm run type-check:web
• pnpm run theme:visual-contract
• pnpm --dir src/web-ui run test:run
• git diff --check