feat(installer): restore Russian UI and setup icon

- re-enable Russian language entry and Russian labels in Inno script

- restore SetupIconFile via MyIconFile define

- pass MyIconFile from build.py with explicit file existence check

build.py

@@ -204,18 +204,24 @@ def build_installer():
     source_dir = os.path.abspath(DIST_DIR)
     output_dir = os.path.abspath("dist")
     iss_path = os.path.abspath(INSTALLER_SCRIPT)
+    icon_path = os.path.abspath(ICON_PATH)
     print(f"[INFO] ISCC source dir: {source_dir}")
     print(f"[INFO] ISCC output dir: {output_dir}")
     print(f"[INFO] ISCC script: {iss_path}")
+    print(f"[INFO] ISCC icon path: {icon_path}")
     if not os.path.exists(source_dir):
         print(f"[ERROR] Source dir does not exist: {source_dir}")
         sys.exit(1)
     if not os.path.exists(iss_path):
         print(f"[ERROR] Installer script does not exist: {iss_path}")
         sys.exit(1)
+    if not os.path.exists(icon_path):
+        print(f"[ERROR] Icon file does not exist: {icon_path}")
+        sys.exit(1)
     command = [
         iscc_path,
         f"/DMyAppVersion={VERSION}",
+        f"/DMyIconFile={icon_path}",
         f"/O{output_dir}",
         iss_path,
     ]