REFACTOR(repo): simplify project structure

- Move services/nextjs/ to nextjs/
- Move Dockerfile.prod to Dockerfile at root
- Remove deploy/ folder (K8s manifests moved to K3S-HOME/web-apps)
- Remove .gitea/ workflows
- Update GitHub Actions for new structure
- Remove develop branch triggers

nextjs/components/ui/mode-toggle.tsx

@@ -0,0 +1,38 @@
+"use client"
+
+import * as React from "react"
+import { Moon, Sun } from "lucide-react"
+import { useTheme } from "next-themes"
+
+import { Button } from "./button"
+
+export function ModeToggle() {
+  const [mounted, setMounted] = React.useState(false)
+  const { theme, setTheme } = useTheme()
+
+  // useEffect only runs on the client, so now we can safely show the UI
+  React.useEffect(() => {
+    setMounted(true)
+  }, [])
+
+  if (!mounted) {
+    return null
+  }
+
+  const toggleTheme = () => {
+    setTheme(theme === "dark" ? "light" : "dark")
+  }
+
+  return (
+    <Button 
+      variant="ghost" 
+      size="icon"
+      onClick={toggleTheme}
+    >
+      <Sun className="h-[1.2rem] w-[1.2rem] rotate-0 scale-100 transition-all dark:-rotate-90 dark:scale-0" />
+      <Moon className="absolute h-[1.2rem] w-[1.2rem] rotate-90 scale-0 transition-all dark:rotate-0 dark:scale-100" />
+      <span className="sr-only">Toggle theme</span>
+    </Button>
+  )
+}
+