chore(deps): upgrade fastify5/next16/prisma7/react19 and fix npm audi…

[eigger]

…t vulnerabilities

Resolves all 12 npm audit findings (3 moderate, 8 high, 1 critical) plus follow-on transitive vulnerabilities surfaced by the upgrades themselves:

• fastify 4->5, @fastify/jwt 8->10, and the cors/multipart/rate-limit/websocket plugins to their Fastify-5-compatible majors (websocket v9+ changed its handler signature from connection.socket to a direct WebSocket param)
• next 14->16 (skipping 15), react/react-dom 18->19, react-leaflet 4->5
• node-cron 3->4, zod 3->4, typescript 5->6 (7 held back: Next 16.2.11 doesn't yet detect the new native TS7 compiler), recharts, mqtt, bcryptjs 2->3
• prisma/@prisma/client 5->7: now requires a driver adapter (@prisma/adapter-pg), a prisma.config.ts, and a generated-client output path. Updated the Docker build (Node 22, ships prisma.config.ts) and the migrate deploy invocations in docker-compose.prod.yml/CI to pass --config explicitly, since the container's CWD no longer matches where the config lives. Verified with a real Docker build + container run against Postgres.
• Added npm overrides for postcss/sharp (bundled by next) and find-my-way/valibot (bundled by prisma's unused prisma dev tooling) to eliminate the last few vulnerable nested copies -> npm audit: 0 vulnerabilities

Verified via full typecheck, 84 tests, next build, a real Docker image build/run against Postgres, and browser smoke tests (login, maps, charts).