feat: harden dedupe runtime and NAS deployment

am_deduper/l2.py

@@ -3,6 +3,7 @@ from __future__ import annotations
 from pathlib import Path
 from .acoustic import chromaprint, similarity
 from .arbitration import choose_winner, is_version_conflict, score
+from .exact import hardlink_duplicate
 from .db import connect
 from .constants import QUARANTINE_SUBDIR, TRASH_SUBDIR
 
@@ -22,7 +23,7 @@ def find_candidates(conn,row):
     return conn.execute("SELECT * FROM audio_tracks WHERE id!=? AND status IN ('active','hardlinked') AND duration IS NOT NULL AND duration BETWEEN ? AND ?", (row["id"],d-DURATION_DELTA,d+DURATION_DELTA)).fetchall()
 
 
-def acoustic_dedupe(db_path: Path, root: Path) -> dict:
+def acoustic_dedupe(db_path: Path, root: Path, dry_run: bool = False) -> dict:
     stats={"checked":0,"equivalent":0,"review":0,"unique":0,"errors":0}
     with connect(db_path) as conn:
         rows=conn.execute("SELECT * FROM audio_tracks WHERE status='active' ORDER BY id").fetchall()
@@ -47,12 +48,11 @@ def acoustic_dedupe(db_path: Path, root: Path) -> dict:
             winner=choose_winner([row,c]); loser=c if winner["id"]==row["id"] else row
             lp=Path(loser["file_path"]); wp=Path(winner["file_path"])
             if lp.exists() and wp.exists():
-                trash=root/TRASH_SUBDIR
-                trash.mkdir(parents=True,exist_ok=True)
-                target=trash/lp.name
-                n=1
-                while target.exists(): target=trash/f"{lp.stem}.{n}{lp.suffix}"; n+=1
-                lp.replace(target)
-                conn.execute("UPDATE audio_tracks SET status='trashed',file_path=?,trashed_at=CURRENT_TIMESTAMP,review_status=?,updated_at=CURRENT_TIMESTAMP WHERE id=?",(str(target),f"equivalent={sim:.3f};winner={wp}",loser["id"]))
+                # Confirmed same-version acoustic match keeps the user's logical
+                # path. The physical data is shared via a hard link.
+                if lp.stat().st_ino != wp.stat().st_ino:
+                    if not dry_run:
+                        hardlink_duplicate(lp, wp)
+                        conn.execute("UPDATE audio_tracks SET status='hardlinked',review_status=?,updated_at=CURRENT_TIMESTAMP WHERE id=?", (f"acoustic={sim:.3f};winner={wp}", loser["id"]))
                 stats["equivalent"]+=1
     return stats