fix: commit paraglide output to git; remove compile from prepare script

paraglide-js fetches its plugin from cdn.jsdelivr.net at compile time.
In CI (no outbound internet access), this silently produces an empty
_index.js, causing svelte-check to fail with 'not a module' errors.

Fix:
- Commit all generated src/lib/paraglide/ files to git (removing
  the auto-generated .gitignore that was hiding them)
- Simplify prepare script to only run svelte-kit sync
- Add separate 'npm run paraglide' script for developers to
  regenerate when messages/*.json source files change

ui/package.json

@@ -7,7 +7,8 @@
 		"dev": "vite dev",
 		"build": "vite build",
 		"preview": "vite preview",
-		"prepare": "paraglide-js compile --project ./project.inlang --outdir ./src/lib/paraglide && node -e \"const fs=require('fs'),f='./src/lib/paraglide/messages.js',c=fs.readFileSync(f,'utf8').split('\\n').filter(l=>!l.includes('export * as m')&&!l.includes('enabling auto-import')).join('\\n');fs.writeFileSync(f,c)\" && svelte-kit sync || echo ''",
+		"prepare": "svelte-kit sync || echo ''",
+		"paraglide": "paraglide-js compile --project ./project.inlang --outdir ./src/lib/paraglide && node -e \"const fs=require('fs'),f='./src/lib/paraglide/messages.js',c=fs.readFileSync(f,'utf8').split('\\n').filter(l=>!l.includes('export * as m')&&!l.includes('enabling auto-import')).join('\\n');fs.writeFileSync(f,c)\"",
 		"check": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json",
 		"check:watch": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json --watch"
 	},