fix: restore ae855f8 commit pin with shallow clone, keep GPU duration at 100/60

Latest LTX-2 main (f4d0c1e, Mar 30) removed decode_video API causing
ImportError. Restore ae855f8 pin using shallow clone + fetch for faster
startup. GPU durations restored to match original linoyts space.

https://claude.ai/code/session_01LUcTyxgZnDsH1AN59QuLKb

app.py

@@ -38,9 +38,13 @@ if _tv.returncode == 0:
 LTX_REPO_URL = "https://github.com/Lightricks/LTX-2.git"
 LTX_REPO_DIR = os.path.join(os.path.dirname(os.path.abspath(__file__)), "LTX-2")
 
+LTX_COMPATIBLE_COMMIT = "ae855f8"  # Pin to 2026-03-11 (compatible API)
+
 if not os.path.exists(LTX_REPO_DIR):
-    print(f"Cloning {LTX_REPO_URL} (latest main)...")
-    subprocess.run(["git", "clone", LTX_REPO_URL, LTX_REPO_DIR], check=True)
+    print(f"Cloning {LTX_REPO_URL} at commit {LTX_COMPATIBLE_COMMIT}...")
+    subprocess.run(["git", "clone", "--depth", "1", LTX_REPO_URL, LTX_REPO_DIR], check=True)
+    subprocess.run(["git", "-C", LTX_REPO_DIR, "fetch", "--depth", "1", "origin", LTX_COMPATIBLE_COMMIT], check=True)
+    subprocess.run(["git", "-C", LTX_REPO_DIR, "checkout", LTX_COMPATIBLE_COMMIT], check=True)
 
 print("Installing ltx-core and ltx-pipelines from cloned repo...")
 subprocess.run(