feat: scaffold PulseNode dashboard (M1)

Next.js 16 + TypeScript + Tailwind v4 app with a YAML-driven config
system: schema validation (zod), .env interpolation, and a widget
registry rendering bookmark/search/group widgets. CSS custom
properties (--pn-*) drive theming and are overridable from
config.yml's theme.variables. Config load errors surface as a
readable error page instead of crashing the app.

Hot reload, docker/system/http collectors, and the WebSocket push
layer land in later milestones per the approved plan.

prompt.txt

@@ -0,0 +1,15 @@
+Please design detailed a plan for a magnificent and sophisticated dashboard web app:
+
+- The app uses pnpm, tailwindcss@4 and react / next.js
+- The app monitors system, docker, API endpoints, etc.
+- The app is highly configurable through a configuration yml file
+- The app can hot load the configuration file
+- The app stores secrets in an .env file and interpolates them in the configuration file
+- The app contains plenty of widgets, which can be configured
+- The app offers widgets for all services in Projekte/stacks
+- The app is configurable with CSS variables.
+- The app offers browser real-time updates via WebSockets
+- The app is deployable via docker (compose)
+
+References:
+- https://github.com/gethomepage/homepage