deps(ui): bump @types/node from EOL Node 12 to current LTS

@types/node is pinned at ^12.20.33 in both ui/packages/ce/package.json and ui/packages/shared/package.json. Node 12 has been EOL since April 2022.

Symptoms:

• pnpm install warns about unmet peer deps from vitest 3.x and vite 6.x, both of which require @types/node@^18.0.0 || ^20.0.0 || >=22.0.0.
• Dependabot keeps opening patch PRs within the EOL major (most recent: #331, 12.20.33 -> 12.20.55), which fixes nothing.

Proposed fix: bump @types/node to ^22 (current LTS) in both ce and shared. Verify build/tests after — runtime CI/Docker images already run modern Node, so this should be a pure type-level change.

Closes dependabot PR #331 once landed.