build(deps): update Rust and UI dependencies

[smiggleworth]

Refresh the outstanding Rust and UI dependency branch on current main. Upgrade Brotli to 9 and related Rust lockfile dependencies; update Vite+ to 0.3.0, its compatible browser adapter to 4.1.11, PostCSS, Playwright, and Autoprefixer. Preserve Midge at the already validated 4fe106ce revision. Application code and protocol contracts are unchanged.

Validation:

• Rust workspace: 2,187 tests passed, 0 failed, 1 existing ignored test; formatting and strict all-target/all-feature Clippy passed.
• UI: clean npm install; Askr freshness and analyzer; generated-adapter check; formatting, lint, type checking, all 145 unit tests, and production build passed.
• Local browser validation could not start because the Chrome CDN download timed out twice. Hosted frontend CI passed the container build, production-preview smoke, and all 279 browser route tests. Hosted backend CI passed the workspace suite, both state-model variations, and parallel tests. Both checks passed on 813fa813.

No issue: dependency maintenance for the remaining unmerged branch.

AI assistance: Codex rebased the existing dependency work, preserved the newer Midge pin, refreshed packages required by CI, and reviewed the lockfile changes and final dependency graph.