Fix branding: live updates on save, reset clears everything, show defaults

- Clear inline preview styles before persisting CSS on save to avoid
  specificity conflicts that required Ctrl+Shift+R
- Reset to Defaults now deletes uploaded images and clears logoText
- ColorPicker emits value on Solid/Gradient toggle for instant preview
- Show default color swatch with dashed border when field is cleared
- persistThemeCSS now handles background-image rules like server-side

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

src/lib/utils/theme-persist.ts

@@ -74,6 +74,21 @@ export function persistThemeCSS(theme: TenantThemeData) {
 		if (theme.darkCardOpacity < 1) darkVars.push(`  --card-backdrop-blur: blur(8px);`);
 	}
 
+	// Handle background images
+	const extraRules: string[] = [];
+	if (theme.lightPageBgImage) {
+		extraRules.push(`.layout-page-bg { background-image: url('${theme.lightPageBgImage}'); }`);
+	}
+	if (theme.lightNavBgImage) {
+		extraRules.push(`.layout-nav-bg { background-image: url('${theme.lightNavBgImage}'); }`);
+	}
+	if (theme.darkPageBgImage) {
+		extraRules.push(`html.dark .layout-page-bg { background-image: url('${theme.darkPageBgImage}'); }`);
+	}
+	if (theme.darkNavBgImage) {
+		extraRules.push(`html.dark .layout-nav-bg { background-image: url('${theme.darkNavBgImage}'); }`);
+	}
+
 	let css = '';
 	if (lightVars.length > 0) {
 		css += `:root {\n${lightVars.join('\n')}\n}\n`;
@@ -81,6 +96,9 @@ export function persistThemeCSS(theme: TenantThemeData) {
 	if (darkVars.length > 0) {
 		css += `html.dark {\n${darkVars.join('\n')}\n}\n`;
 	}
+	if (extraRules.length > 0) {
+		css += extraRules.join('\n') + '\n';
+	}
 
 	// Find or create the <style id="tenant-theme"> element
 	let styleEl = document.getElementById('tenant-theme') as HTMLStyleElement | null;