Fix Kaggle trigger 401: pass credentials as env vars instead of KAGGLE_CONFIG_DIR

Newer kaggle CLI ignores KAGGLE_CONFIG_DIR; pass KAGGLE_USERNAME and KAGGLE_KEY
directly as environment variables so the CLI authenticates correctly.

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

app.py

@@ -19,7 +19,6 @@ import io
 import json
 import os
 import sys
-import tempfile
 import threading
 from datetime import datetime, timezone
 from pathlib import Path
@@ -619,7 +618,7 @@ def _trigger_kaggle_training(lang: str = "bam") -> str:
     if not KAGGLE_USERNAME or not KAGGLE_KEY:
         return "⚠️ KAGGLE_USERNAME / KAGGLE_KEY not set in Space secrets."
 
-    import subprocess, tempfile, shutil
+    import subprocess
 
     notebooks_dir = ROOT / "notebooks"
     meta_file     = notebooks_dir / "kernel-metadata.json"
@@ -630,28 +629,19 @@ def _trigger_kaggle_training(lang: str = "bam") -> str:
     if not meta_file.exists():
         return "❌ notebooks/kernel-metadata.json not found in Space."
 
-    # Write kaggle.json to a temp dir so the CLI authenticates
-    with tempfile.TemporaryDirectory() as tmpdir:
-        kaggle_cfg = Path(tmpdir) / ".kaggle"
-        kaggle_cfg.mkdir()
-        creds_file = kaggle_cfg / "kaggle.json"
-        creds_file.write_text(
-            json.dumps({"username": KAGGLE_USERNAME, "key": KAGGLE_KEY}),
-            encoding="utf-8",
-        )
-        creds_file.chmod(0o600)
-
-        env = {
-            **__import__("os").environ,
-            "KAGGLE_CONFIG_DIR": str(kaggle_cfg),
-            "PYTHONUTF8": "1",
-            "PYTHONIOENCODING": "utf-8",
-        }
-
-        result = subprocess.run(
-            ["kaggle", "kernels", "push", "-p", str(notebooks_dir)],
-            capture_output=True, text=True, timeout=60, env=env,
-        )
+    # Pass credentials directly as env vars (newer kaggle CLI ignores KAGGLE_CONFIG_DIR)
+    env = {
+        **os.environ,
+        "KAGGLE_USERNAME": KAGGLE_USERNAME,
+        "KAGGLE_KEY": KAGGLE_KEY,
+        "PYTHONUTF8": "1",
+        "PYTHONIOENCODING": "utf-8",
+    }
+
+    result = subprocess.run(
+        ["kaggle", "kernels", "push", "-p", str(notebooks_dir)],
+        capture_output=True, text=True, timeout=60, env=env,
+    )
 
     if result.returncode == 0:
         output = (result.stdout or "").strip()