The list_gmail_filters, create_gmail_filter, and delete_gmail_filter
tools were implemented in gmail_tools.py but not exposed in the
tool_tiers.yaml configuration, causing them to be filtered out when
using the tier-based tool loading system.
Also added get_gmail_attachment_content which was similarly missing.
Changes:
- Added get_gmail_attachment_content to extended tier
- Added list_gmail_filters to extended tier
- Added create_gmail_filter to extended tier
- Added delete_gmail_filter to extended tier
- Removed duplicate get_gmail_attachment_content entry
39c9faca1b