Task_179

[sagarikapatha]

Implemented independent date filter support for Volunteer Activity Trend and Volunteers by Location.

Changes:

• Added build_date_filter_trend()
• Added build_date_filter_location()
• Added get_grouping()
• Updated get_volunteer_activity_trend() to support 7D, 30D, 1Y, All, and Custom filters
• Updated get_volunteers_by_location() to support independent date filtering
• Changed trend response key from month to period
• Kept Volunteers by Location country aggregation logic unchanged
• Added LOCAL_DB_TEST mode using CSV files from the sql folder

Testing:

• python -m py_compile volunteer_application_analytics.py
• LOCAL_DB_TEST=true python volunteer_application_analytics.py
• Verified All response locally
• Verified 30D daily grouped response locally