Add batched glyph previews

[kostyafarber]

Summary

• add TanStack Query at the renderer composition root with local-workspace defaults
• add a lightweight batched glyph-preview DTO and NAPI/workspace query
• adapt the merged FontProjection into flattened SVG paths and root advances without hydrating editable renderer glyph models
• load stable visible-grid chunks by document, internal design location, and glyph identity; cached chunks survive fast scrolling and stale location results cannot replace the active location
• preserve the distinction between missing glyphs and present blank glyphs
• align local development, CI, performance jobs, and pnpm engine enforcement on Node 24 LTS

Why

Large designspace fonts made the home grid hydrate complete live glyph models, interpolation data, and component trees for every visible cell. That work blocked useful previews and produced flicker while scrolling. This change keeps authoring semantics in shift-font, exposes only the compact projection the grid needs, and lets TanStack Query own fixed-chunk reuse and stale-result isolation.

Closes #150.

Validation

• cargo test -p shift-font -p shift-wire
• cargo check -p shift-bridge
• cargo clippy --workspace --all-targets -- -D warnings
• pnpm typecheck
• pnpm format:check
• pnpm lint:check
• pnpm install --frozen-lockfile --ignore-scripts under Node 24
• complete pre-commit suite, including Rust tests, dead-code checks, and pnpm test