fix(ui): unify legacy surfaces with liquid glass

[Qiyuanqiii]

Summary

• unify legacy dialogs, history/sidebar states, workbench panels, utility pages, and model/settings surfaces with the current liquid-glass theme tokens
• redesign the Run creation dialog across light, dark, and glass themes, including responsive mobile behavior
• remove residual orange/beige page styling, standardize JetBrains Mono typography, and restore readable muted-text contrast
• add reduced-motion, reduced-transparency, increased-contrast, and Windows forced-colors fallbacks

Root cause

The Run creation dialog is rendered outside .prayu-shell, so newer theme aliases did not reach it. Several sidebar and auxiliary-page selectors also retained hard-coded colors from the older warm theme. A final compatibility layer now maps legacy variables to the active --prayu-* tokens and normalizes those remaining surfaces without changing their layout contracts.

Validation

• npm run check:api
• npm test -- --run — 59 test files, 238 tests passed
• npm run build
• Playwright visual QA in light, dark, and glass themes at 923×830, 1280×820, and 390×844
• browser console: 0 errors, 0 warnings
• mobile dialog: no horizontal overflow