Upgrade to pnpm 11 and resolve dependency alerts

[kostyafarber]

Summary

• upgrade the workspace and global-compatible configuration to pnpm 11.18.0
• move pnpm settings into pnpm-workspace.yaml, preserve the hoisted linker, and explicitly allow reviewed install scripts
• update Electron, Forge, Vite, Vitest, React, and React Router to patched compatible versions
• replace React Router DOM compatibility imports with the React Router 8 API
• replace vulnerable transitive versions with narrow parent-specific overrides
• remove confirmed-unused dependencies and add pnpm check-deps

Security

• reduced the audit result from 89 advisories to 0
• reduced security overrides to eight targeted entries for upstream ranges without patched releases

Verification

• pnpm install --frozen-lockfile
• pnpm check-deps
• pnpm peers check
• pnpm format:check
• pnpm lint:check
• pnpm typecheck
• pnpm test
• pnpm --filter @shift/desktop package