stemd: AUTO_SCAN=0 runs on request only (Stem Now)

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

server/stemd.py

@@ -20,6 +20,7 @@ Settings (environment):
   MODEL       roformer_bs_sw   any id from stemify/catalog.py
   DEVICE      cuda             cuda, cuda:N or cpu
   RESCAN_MIN  30               minutes between scans once caught up
+  AUTO_SCAN   1                0 = never scan the library; only separate Stem Now requests
   FP16        1                half precision on the GPU
   OVERLAP / SEGMENT / SHIFTS   as in the desktop app's settings
 """
@@ -47,6 +48,7 @@ MODELS_DIR = os.environ.get("MODELS_DIR", "/models")
 MODEL = os.environ.get("MODEL", "roformer_bs_sw")
 DEVICE = os.environ.get("DEVICE", "cuda")
 RESCAN_S = float(os.environ.get("RESCAN_MIN", "30")) * 60
+AUTO_SCAN = os.environ.get("AUTO_SCAN", "1") not in ("0", "false", "no", "")
 FP16 = os.environ.get("FP16", "1") not in ("0", "false", "no", "")
 OVERLAP = float(os.environ.get("OVERLAP", "0.25"))
 SEGMENT = float(os.environ.get("SEGMENT", "0"))
@@ -349,8 +351,13 @@ def main():
     migrate_markers()
     sep = Separator()
     failed = Failed()
+    if not AUTO_SCAN:
+        log("AUTO_SCAN off: only Stem Now requests will be separated")
     while not stop.is_set():
         try:
+            if not AUTO_SCAN:
+                idle(sep, failed, RESCAN_S)
+                continue
             done, used = run_pass(sep, failed)
             if done:
                 log(f"pass finished: {done:,} tracks separated")