Initial scaffold: offertesysteem (clients, projects, quotes, quote_items)

- Next.js 15 + TypeScript + Tailwind, standalone output
- SQLite schema: users, clients, projects, quotes, quote_items
- HMAC-signed sessie-cookie auth
- Dockerfile (Node 22 Alpine, multi-stage)
- create-admin script
- Doel: portal.rikxplatform.nl

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,49 @@
+# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
+
+# dependencies
+/node_modules
+/.pnp
+.pnp.*
+.yarn/*
+!.yarn/patches
+!.yarn/plugins
+!.yarn/releases
+!.yarn/versions
+
+# testing
+/coverage
+
+# next.js
+/.next/
+/out/
+
+# production
+/build
+
+# misc
+.DS_Store
+*.pem
+
+# debug
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+.pnpm-debug.log*
+
+# env files
+.env*
+!.env.example
+
+# data (SQLite database en uploads)
+/data
+
+# claude
+.claude/
+desktop.ini
+
+# vercel
+.vercel
+
+# typescript
+*.tsbuildinfo
+next-env.d.ts