Add project skeleton: CLI pipeline for CD digitization

Modular Python package with Typer CLI (scan/apply/process commands),
Pydantic data models, OCR via Tesseract, LLM-based tracklist parsing,
mutagen audio tagging, M3U playlist generation, and cover processing.
Includes 8 passing tests and ruff lint config.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/musiksammlung/models.py

@@ -0,0 +1,38 @@
+"""Zentrale Datenmodelle für Album, Disc und Track."""
+
+from __future__ import annotations
+
+import re
+
+from pydantic import BaseModel, field_validator
+
+
+class Track(BaseModel):
+    track_number: int
+    title: str
+
+
+class Disc(BaseModel):
+    disc_number: int
+    name: str | None = None  # z.B. "Live in Berlin"
+    tracks: list[Track]
+
+
+class Album(BaseModel):
+    artist: str
+    album: str
+    year: int | None = None
+    discs: list[Disc]
+
+    @field_validator("album", "artist")
+    @classmethod
+    def sanitize_name(cls, v: str) -> str:
+        """Entfernt Zeichen, die in Dateinamen problematisch sind."""
+        return re.sub(r'[<>:"/\\|?*]', "_", v).strip()
+
+    @property
+    def folder_name(self) -> str:
+        """Jellyfin-konformer Ordnername: 'Album (Year)' oder nur 'Album'."""
+        if self.year:
+            return f"{self.album} ({self.year})"
+        return self.album