feat(f5tts): HF-URL Support fuer Custom Checkpoints (aihpi/F5-TTS-German)

_resolve_hf_path wandelt hf://user/repo/path → lokaler Download via
huggingface_hub.hf_hub_download. So kann man in Diagnostic einfach die
HF-Pfade fuer custom Modelle reinschreiben, ohne erst manuell zu
downloaden + zu mounten.

Format: hf://aihpi/F5-TTS-German/F5TTS_Base/model_365000.safetensors
        hf://aihpi/F5-TTS-German/vocab.txt

Diagnostic UI: Placeholders + Labels angepasst mit Beispiel-HF-Pfaden
und Hinweis dass fuer Fine-Tunes "F5TTS_Base" statt "F5TTS_v1_Base"
als Architektur-Name gesetzt werden muss.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

xtts/f5tts/bridge.py

@@ -99,6 +99,33 @@ def _get_f5tts_cls():
     return _F5TTS_cls
 
 
+def _resolve_hf_path(p: str) -> str:
+    """Wenn p mit 'hf://' anfaengt → aus HuggingFace Hub runterladen,
+    lokalen Pfad zurueckgeben. Sonst unveraendert.
+
+    Format: hf://user/repo/path/to/file.ext
+    Beispiel: hf://aihpi/F5-TTS-German/F5TTS_Base/model_365000.safetensors
+    """
+    if not p or not p.startswith("hf://"):
+        return p
+    try:
+        from huggingface_hub import hf_hub_download
+        rest = p[5:]
+        parts = rest.split("/", 2)
+        if len(parts) < 3:
+            logger.warning("Ungueltiges hf:// Format: %s (erwarte hf://user/repo/path)", p)
+            return p
+        repo_id = f"{parts[0]}/{parts[1]}"
+        filename = parts[2]
+        logger.info("HF-Download: %s aus %s", filename, repo_id)
+        local = hf_hub_download(repo_id=repo_id, filename=filename)
+        logger.info("HF-Download fertig: %s", local)
+        return local
+    except Exception as e:
+        logger.exception("HF-Download fehlgeschlagen fuer %s: %s", p, e)
+        return p
+
+
 class F5Runner:
     """Haelt das F5-TTS-Modell. Synthese laeuft im Executor (blocking).
 
@@ -122,14 +149,16 @@ class F5Runner:
 
     def _load_blocking(self) -> None:
         cls = _get_f5tts_cls()
+        ckpt_resolved = _resolve_hf_path(self.ckpt_file) if self.ckpt_file else ""
+        vocab_resolved = _resolve_hf_path(self.vocab_file) if self.vocab_file else ""
         logger.info("Lade F5-TTS '%s' (device=%s, ckpt=%s)...",
-                    self.model_id, F5TTS_DEVICE, self.ckpt_file or "default")
+                    self.model_id, F5TTS_DEVICE, ckpt_resolved or "default")
         self._load_started_at = time.time()
         kwargs = {"model": self.model_id, "device": F5TTS_DEVICE}
-        if self.ckpt_file:
-            kwargs["ckpt_file"] = self.ckpt_file
-        if self.vocab_file:
-            kwargs["vocab_file"] = self.vocab_file
+        if ckpt_resolved:
+            kwargs["ckpt_file"] = ckpt_resolved
+        if vocab_resolved:
+            kwargs["vocab_file"] = vocab_resolved
         self.model = cls(**kwargs)
         elapsed = time.time() - self._load_started_at
         logger.info("F5-TTS geladen in %.1fs (cfg_strength=%.1f, nfe=%d)",