Diff UI update

.gitignore

@@ -36,3 +36,5 @@ npm-debug.log
 /.elixir_ls/
 /.vscode/
 /tmp/
+.claude/settings.local.json
+.tool-versions

assets/build.js

@@ -0,0 +1,71 @@
+const esbuild = require('esbuild')
+const { spawn } = require('child_process')
+const fs = require('fs')
+const path = require('path')
+
+const args = process.argv.slice(2)
+const watch = args.includes('--watch')
+const deploy = args.includes('--deploy')
+
+// Copy static assets to priv/static
+const staticSrc = path.join(__dirname, 'static')
+const staticDest = path.join(__dirname, '..', 'priv', 'static')
+
+function copyDir(src, dest) {
+  fs.mkdirSync(dest, { recursive: true })
+  for (const entry of fs.readdirSync(src, { withFileTypes: true })) {
+    const from = path.join(src, entry.name)
+    const to = path.join(dest, entry.name)
+    entry.isDirectory() ? copyDir(from, to) : fs.copyFileSync(from, to)
+  }
+}
+
+if (fs.existsSync(staticSrc)) copyDir(staticSrc, staticDest)
+
+// Tailwind CSS via CLI
+const twArgs = ['--input', 'css/app.css', '--output', '../priv/static/css/app.css']
+if (watch) twArgs.push('--watch')
+if (deploy) twArgs.push('--minify')
+
+const tailwind = spawn(process.execPath, ['./node_modules/.bin/tailwindcss', ...twArgs], {
+  stdio: 'inherit',
+})
+tailwind.on('error', err => {
+  console.error('tailwindcss error:', err.message)
+  process.exit(1)
+})
+tailwind.on('exit', (code) => {
+  if (code !== 0 && code !== null && !watch) {
+    process.exit(code)
+  }
+})
+
+// esbuild JS bundle
+const esbuildOpts = {
+  entryPoints: ['js/app.js'],
+  bundle: true,
+  target: 'es2017',
+  outdir: '../priv/static/js',
+  minify: deploy,
+  sourcemap: !deploy,
+  logLevel: 'info',
+}
+
+if (watch) {
+  esbuild.context(esbuildOpts).then(ctx => {
+    ctx.watch()
+    // Exit cleanly when Phoenix closes stdin (server shutdown)
+    process.stdin.resume()
+    process.stdin.on('end', () => {
+      ctx.dispose()
+      tailwind.kill()
+      process.exit(0)
+    })
+  }).catch((err) => {
+    console.error('esbuild context error:', err.message)
+    tailwind.kill()
+    process.exit(1)
+  })
+} else {
+  esbuild.build(esbuildOpts).catch(() => process.exit(1))
+}