[sdrpsps]

Summary

This PR introduces the poster generation history drawer, migrates frontend state to Zustand to eliminate re-render cascades, optimizes vendor chunk bundle sizes, and standardizes Tailwind CSS v4 class utilities and diagnostics.

Key Changes

• Poster History: Added persistent IndexedDB-based poster history storage with thumbnail preview, full poster modal view, snapshot configuration restore, copy/share/download actions, and history drawer sheet.
• State Management: Migrated poster studio state to Zustand store, decoupling independent sections and avoiding full studio re-renders.
• Image Sharing & Clipboard: Added utilities for copying PNG blob/URLs directly to system clipboard and sharing via Web Share API with graceful fallbacks.
• Bundle Optimization: Configured Rollup manual chunks for vendor splitting (React core, Base UI / Lucide / Zustand, i18next).
• Tailwind v4 & Diagnostics: Standardized Tailwind CSS v4 utility classes across components, added theme font/color tokens, and configured VS Code language associations for Tailwind CSS.

Verification

• Ran oxlint: 0 errors, 0 warnings.
• Ran tsc -b && vite build: Build completed successfully.
• Ran pytest suite: 130 passed.