Remove WASM numpy_stub, now unnecessary with lazy imports

numpy is lazy-loaded throughout the codebase via the _lazy_import
helpers, so the WASM numpy_stub that patched sys.modules['numpy']
is no longer needed. Delete the stub module and remove its
references from udf_handler.py.

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

Author: kesmit13

singlestoredb/functions/ext/wasm/numpy_stub.py

@@ -24,18 +24,9 @@
 from typing import List
 from typing import Optional
 
-
-# Install numpy stub before importing singlestoredb (which tries to import numpy)
-if 'numpy' not in sys.modules:
-    try:
-        import numpy  # noqa: F401
-    except ImportError:
-        from . import numpy_stub
-        sys.modules['numpy'] = numpy_stub
-
-from singlestoredb.functions.signature import get_signature
-from singlestoredb.functions.ext.rowdat_1 import load as _load_rowdat_1
 from singlestoredb.functions.ext.rowdat_1 import dump as _dump_rowdat_1
+from singlestoredb.functions.ext.rowdat_1 import load as _load_rowdat_1
+from singlestoredb.functions.signature import get_signature
 from singlestoredb.mysql.constants import FIELD_TYPE as ft
 
 try:
@@ -144,7 +135,7 @@ def _is_stdlib_or_infra(mod_name: str, mod_file: str) -> bool:
         """
         # Infrastructure modules that are part of this project
         _infra = frozenset({
-            'udf_handler', 'numpy_stub',
+            'udf_handler',
         })
         if mod_name in _infra:
             return True