Add holiday promotion, snowflakes effect, and Spotify music widget

- Added holiday promotion banner with 2026WITHMARINARA discount code
- Added dismiss functionality for promotion with persistent state
- Implemented snowflakes animation effect with toggle
- Added Spotify music widget above chat input
- Widget matches extension theme colors and positioning
- Added Display Options toggles to show/hide feature toggles
- Improved responsive design and mobile support

src/systems/generation/promptBuilder.js

@@ -16,6 +16,16 @@ import { extensionSettings, committedTrackerData, FEATURE_FLAGS } from '../../co
  */
 export const DEFAULT_HTML_PROMPT = `If appropriate, include inline HTML, CSS, and JS segments whenever they enhance visual storytelling (e.g., for in-world screens, posters, books, letters, signs, crests, labels, etc.). Style them to match the setting's theme (e.g., fantasy, sci-fi), keep the text readable, and embed all assets directly (using inline SVGs only with no external scripts, libraries, or fonts). Use these elements freely and naturally within the narrative as characters would encounter them, including animations, 3D effects, pop-ups, dropdowns, websites, and so on. Do not wrap the HTML/CSS/JS in code fences!`;
 
+/**
+ * Default Spotify music prompt text (customizable by users)
+ */
+export const DEFAULT_SPOTIFY_PROMPT = `If appropriate for the current scene's mood and atmosphere, suggest a song that fits the ambiance. Choose music that enhances the emotional tone, setting, or action of the scene.`;
+
+/**
+ * Spotify format instruction (constant, not editable by users)
+ */
+export const SPOTIFY_FORMAT_INSTRUCTION = `Include it in this exact format: <spotify:Song Title - Artist Name/>.`;
+
 /**
  * Gets character card information for current chat (handles both single and group chats)
  * @returns {string} Formatted character information
@@ -445,6 +455,20 @@ export function generateTrackerInstructions(includeHtmlPrompt = true, includeCon
         instructions += htmlPrompt;
     }
 
+    // Append Spotify music prompt if enabled AND includeHtmlPrompt is true
+    if (extensionSettings.enableSpotifyMusic && includeHtmlPrompt) {
+        // Add separator
+        if (hasAnyTrackers || extensionSettings.enableHtmlPrompt) {
+            instructions += `\n\n`;
+        } else {
+            instructions += `\n`;
+        }
+
+        // Use custom Spotify prompt if set, otherwise use default
+        const spotifyPrompt = extensionSettings.customSpotifyPrompt || DEFAULT_SPOTIFY_PROMPT;
+        instructions += spotifyPrompt + ' ' + SPOTIFY_FORMAT_INSTRUCTION;
+    }
+
     return instructions;
 }