Add TypeScript theme generator for doki-master-theme palettes

Generates one Gitea-compatible CSS theme file per doki-master-theme
definition (88 themes). Each file contains a gitea-theme-meta-info
block and a :root block with the full set of CSS custom properties
derived from the character's colour palette.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/cssWriter.ts

@@ -0,0 +1,26 @@
+import type { ThemeConfig } from './types.js';
+
+export function renderThemeCSS(theme: ThemeConfig, variables: Record<string, string>): string {
+  const isDark = theme.colorScheme === 'dark';
+  const lines: string[] = [];
+
+  lines.push('gitea-theme-meta-info {');
+  lines.push(`  --theme-display-name: "${theme.displayName}";`);
+  lines.push(`  --theme-color-scheme: "${theme.colorScheme}";`);
+  lines.push('}');
+  lines.push('');
+  lines.push(':root {');
+
+  for (const [name, value] of Object.entries(variables)) {
+    lines.push(`  ${name}: ${value};`);
+  }
+
+  // Native CSS properties at the end (not custom properties)
+  lines.push(`  accent-color: var(--color-accent);`);
+  lines.push(`  color-scheme: ${isDark ? 'dark' : 'light'};`);
+
+  lines.push('}');
+  lines.push('');
+
+  return lines.join('\n');
+}