Switch to datastar-pro and stop tracking downloaded libs

Datastar-pro is fetched from a private Gitea repo (ryan/vendor-libs)
using VENDOR_TOKEN for CI/Docker builds, with a local fallback from
../optional/ for development. DaisyUI is pinned to v5.5.19 instead of
tracking latest. Downloaded files are now gitignored and fetched at
build time via 'task download', which is a dependency of both build
and live tasks.

assets/css/input.css

@@ -1,8 +1,8 @@
 @import 'tailwindcss';
 
-@source not "./daisyui{,*}.mjs";
-@plugin "./daisyui.mjs";
-@plugin "./daisyui-theme.mjs" {
+@source not "./daisyui/daisyui{,*}.js";
+@plugin "./daisyui/daisyui.js";
+@plugin "./daisyui/daisyui-theme.js" {
   name: "stealth";
   default: true;
   color-scheme: light;

assets/js/README.md

@@ -0,0 +1 @@
+Downloaded by cmd/downloader at build time.