feat: Standard-Dateiname aus Kanal, Titel und Datum des Videos

- yt_untertitel.default_name(): <Kanal>_<Titel>_<Datum>, z. B.
  John_Mearsheimer_Offensive_Realism_Episode_1_Origins_of_the_War_In_Ukraine_2026-07-30
- Bindestriche/Punkte im Wort bleiben, Kanal max. 40, Titel max. 60 Zeichen
  an Wortgrenze; ohne Kanal und Titel die Video-ID
- Gilt ohne -o/-n in extract_text.py (statt output.txt), yt_untertitel.py
  und rede_korrigieren.py -u (statt Video-ID)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

yt_untertitel.py

@@ -4,12 +4,17 @@ als Eingabe für vtt2txt.py bzw. rede_korrigieren.py."""
 from pathlib import Path
 import argparse
 import json
+import re
 import shutil
 import subprocess
 import tempfile
 
 YT_DLP = "yt-dlp"
 
+NAME_WORD = re.compile(r"\w+(?:[-.]\w+)*")  # keeps "Krone-Schmalz", "28.03.2026"
+MAX_CHANNEL_CHARS = 40
+MAX_TITLE_CHARS = 60
+
 
 def run_yt_dlp(arguments):
     """Run yt-dlp in a temporary working directory.
@@ -80,6 +85,33 @@ def choose_track(info, lang):
     return None
 
 
+def name_part(text, limit):
+    """Words of `text` joined by "_", cut at a word boundary after `limit` chars."""
+    words = NAME_WORD.findall(text or "")
+    part = ""
+    for word in words:
+        candidate = f"{part}_{word}" if part else word
+        if len(candidate) > limit:
+            break
+        part = candidate
+    # A single overlong word is cut rather than dropped
+    return part or (words[0][:limit] if words else "")
+
+
+def default_name(info):
+    """File name without extension from channel, title and upload date.
+
+    "John_Mearsheimer_Offensive_Realism_Episode_1_Origins_of_the_War_In_Ukraine_2026-07-30"
+    """
+    date = info.get("upload_date") or ""
+    parts = [
+        name_part(info.get("channel") or info.get("uploader"), MAX_CHANNEL_CHARS),
+        name_part(info.get("title"), MAX_TITLE_CHARS),
+        f"{date[:4]}-{date[4:6]}-{date[6:]}" if re.fullmatch(r"\d{8}", date) else "",
+    ]
+    return "_".join(p for p in parts if p) or info.get("id") or "video"
+
+
 def available_tracks(info):
     """Manual tracks and the automatic ones usable for this program."""
     manual = sorted((info.get("subtitles") or {}).keys())
@@ -126,7 +158,7 @@ def parse_args():
     parser.add_argument("-u", "--url", required=True, help="YouTube-URL des Videos")
     parser.add_argument(
         "-n", "--name",
-        help="Dateiname ohne Endung, z. B. Lahnstein (Standard: Video-ID)",
+        help="Dateiname ohne Endung, z. B. Lahnstein (Standard: <Kanal>_<Titel>_<Datum>)",
     )
     parser.add_argument(
         "-l", "--lang", default="de", help="Sprache der Untertitel (Standard: de)"
@@ -158,7 +190,7 @@ def main():
     print(f"Lade {kind} Untertitel „{track}“ …", flush=True)
 
     args.dir.mkdir(parents=True, exist_ok=True)
-    target_base = args.dir / (args.name or info["id"])
+    target_base = args.dir / (args.name or default_name(info))
     download(args.url, track, is_auto, target_base)
 
     target = Path(f"{target_base}.{track}.vtt")