chore: initial project structure and root configuration

Adds root-level config files: solution (.slnx), NuGet, global.json,
Docker Compose files for all services (API, dashboard, website, finder,
admin), environment example, and developer documentation.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,40 @@
+# Dependencies
+node_modules/
+web/dashboard/node_modules/
+web/dashboard/.next/
+.pnpm-store/
+
+# Build outputs
+.next/
+out/
+build/
+dist/
+bin/
+obj/
+
+# IDE
+.vs/
+*.user
+*.suo
+.idea/
+.cursor/
+
+# Claude Code (local settings and skill data — not project code)
+.claude/settings.local.json
+.claude/skills/
+.config/
+
+# Environment
+.env*
+!.env.example
+
+# Flutter
+mobile/meezi_app/.dart_tool/
+mobile/meezi_app/build/
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Logs
+*.log