fix: correct zero-safe pathconf checks and connectivity prefix match

- Use `is not None` for pathconf values so 0 is not silently dropped
- Broaden connectivity prefix check to catch bare "connectivity" key

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

hbd/client/plugins/filesystem_info.py

@@ -127,15 +127,15 @@ class FilesystemInfoPlugin(InfoPlugin):
                     try:
                         # Maximum filename length
                         max_name = os.pathconf(partition.mountpoint, 'PC_NAME_MAX')
-                        if max_name:
+                        if max_name is not None:
                             fs_info['maxfile'] = max_name
                     except (OSError, ValueError):
                         pass
-                    
+
                     try:
                         # Maximum path length
                         max_path = os.pathconf(partition.mountpoint, 'PC_PATH_MAX')
-                        if max_path:
+                        if max_path is not None:
                             fs_info['maxpath'] = max_path
                     except (OSError, ValueError):
                         pass