Fix iPod transfer: create Music/F00 dir and iTunesCDB on first run

- copy_track_to_ipod: create target directory via os.makedirs
- sync_itunescdb: create iTunesCDB from scratch if missing
- sync_itunescdb: create iTunesCDB.ext with hash if missing

src/ipod_nano7_db.py

@@ -206,6 +206,7 @@ class Nano7Database:
 
         target_dir = self.find_free_music_dir()
         target_path = os.path.join(self.music_base, target_dir, new_name)
+        os.makedirs(os.path.dirname(target_path), exist_ok=True)
         shutil.copy2(filepath, target_path)
 
         relative_path = f"{target_dir}/{new_name}"
@@ -1102,7 +1103,15 @@ class Nano7Database:
         # Compute new SHA1 hash
         new_hash = hashlib.sha1(lib_data).hexdigest()
         
-        # Read existing iTunesCDB to extract the header (first 244 bytes)
+        # Read existing iTunesCDB to extract the header (first bytes before zlib)
+        if not os.path.exists(self.cdb_path):
+            header = b"\x00" * 244
+            header = b"mhfd" + struct.pack("<I", 244) + header[8:]
+            compressed = zlib.compress(lib_data)
+            with open(self.cdb_path, "wb") as f:
+                f.write(header + compressed)
+            logger.info(f"Created iTunesCDB: compressed={len(compressed)} bytes")
+        else:
             with open(self.cdb_path, "rb") as f:
                 cdb_data = f.read()
 
@@ -1126,6 +1135,9 @@ class Nano7Database:
                 f.write(header + compressed)
         
         # Update hash in iTunesCDB.ext
+        if not os.path.exists(self.cdb_ext_path):
+            ext_content = f"[iTunesCDB]\nitunesdb_hash={new_hash}\n"
+        else:
             with open(self.cdb_ext_path, "r") as f:
                 ext_content = f.read()