feat: integrate Sensei Spook mascot in 4 stances, speech bubbles, and style updates

lib/watermark.ts

@@ -0,0 +1,35 @@
+import { spawn } from "child_process";
+import path from "path";
+import fs from "fs";
+
+/**
+ * Executes the Python watermark processor on an image file on disk.
+ * Applies:
+ * 1. School logo without background in top-left corner
+ * 2. Scannable official WeChat QR code in bottom-right corner
+ * 3. Bottom text: '上海健志空手道馆 · Shanghai Karate Club · Est. 2008'
+ */
+export async function applyWatermarkToFile(filePath: string): Promise<void> {
+  return new Promise((resolve, reject) => {
+    if (!fs.existsSync(filePath)) {
+      return resolve();
+    }
+
+    const scriptPath = path.join(process.cwd(), "watermark_processor.py");
+    const py = spawn("python", [scriptPath, filePath, filePath]);
+
+    py.on("close", (code) => {
+      if (code === 0) {
+        resolve();
+      } else {
+        console.warn(`[Watermark] Python watermark process exited with code ${code}`);
+        resolve(); // Graceful fallback
+      }
+    });
+
+    py.on("error", (err) => {
+      console.warn("[Watermark] Failed to spawn watermark process:", err);
+      resolve(); // Graceful fallback
+    });
+  });
+}