fix: replace print() with logger.warning() in extensions catalog warnings

Print statements to stderr are not appropriate for library code that may
be consumed by tools or tests. Replaced with logger.warning() for proper
log management. Removed unused local sys imports.

Author: Quratulain-bilal

src/specify_cli/extensions/__init__.py

@@ -12,6 +12,7 @@
 import errno
 import hashlib
 import json
+import logging
 import os
 import re
 import shutil
@@ -45,6 +46,8 @@
 from ..catalogs import CatalogStackBase
 from ..shared_infra import verify_archive_sha256
 
+logger = logging.getLogger(__name__)
+
 _FALLBACK_CORE_COMMAND_NAMES = frozenset(
     {
         "analyze",
@@ -3508,18 +3511,15 @@ def get_active_catalogs(self) -> List[CatalogEntry]:
         Raises:
             ValidationError: If a catalog URL is invalid
         """
-        import sys
-
         # 1. SPECKIT_CATALOG_URL env var replaces all defaults for backward compat
         if env_value := os.environ.get("SPECKIT_CATALOG_URL"):
             catalog_url = env_value.strip()
             self._validate_catalog_url(catalog_url)
             if catalog_url != self.DEFAULT_CATALOG_URL:
                 if not getattr(self, "_non_default_catalog_warning_shown", False):
-                    print(
-                        "Warning: Using non-default extension catalog. "
+                    logger.warning(
+                        "Using non-default extension catalog. "
                         "Only use catalogs from sources you trust.",
-                        file=sys.stderr,
                     )
                     self._non_default_catalog_warning_shown = True
             return [
@@ -3743,8 +3743,6 @@ def _get_merged_extensions(
         Raises:
             ExtensionError: If all catalogs fail to fetch
         """
-        import sys
-
         active_catalogs = self.get_active_catalogs()
         merged: Dict[str, Dict[str, Any]] = {}
         any_success = False
@@ -3754,9 +3752,8 @@ def _get_merged_extensions(
                 catalog_data = self._fetch_single_catalog(catalog_entry, force_refresh)
                 any_success = True
             except ExtensionError as e:
-                print(
-                    f"Warning: Could not fetch catalog '{catalog_entry.name}': {e}",
-                    file=sys.stderr,
+                logger.warning(
+                    "Could not fetch catalog '%s': %s", catalog_entry.name, e,
                 )
                 continue