Upgrade Next.js and project dependencies

[austin-smith]

What Changed

• Upgrade Next.js and eslint-config-next from 16.2.9 to 16.3.0.
• Refresh eligible same-major React, Tailwind CSS, Radix UI, CodeMirror, Motion, Lucide, Vitest, shadcn, ESLint, and type packages.
• Reduce the minimum package age from seven days to three days.
• Regenerate and deduplicate the pnpm lockfile, including a single compatible CodeMirror dependency graph.
• Keep the Next-generated agent guidance required by Next.js 16.3.

Why

Keep the application on current, policy-eligible dependency releases while preserving Node 24, TypeScript 5.9, and ESLint 9 compatibility. The lockfile refresh also removes duplicate CodeMirror instances that would otherwise cause nominal TypeScript conflicts.

Validation

• pnpm install --frozen-lockfile
• pnpm lint
• pnpm test — 13 files and 74 tests passed
• pnpm exec tsc --noEmit --incremental false
• pnpm build
• pnpm dedupe --check
• pnpm audit --prod — no critical, high, or moderate findings
• Desktop and mobile browser smoke tests for dashboard, admin dialogs, Radix Select, and CodeMirror
• Clean Docker image build and containerized HTTP startup checks