Add brighter end to orange gradient

Bump image to Debian Trixie for sqlite with JSONB

Compile `!=` to `IS NOT` for better null handling.

If an activity doesn't have the key, better to not filter it out when
using a != expression.

    NULL != 1      -> NULL
    NULL IS NOT 1  -> true

Add log line for Strava webhook upload

Fix Docker image path and add Strava webhook setup

Updated Docker commands to use the correct image path and added instructions for enabling Strava webhook endpoints.

Fixes #10

Change Docker workflow to trigger on main branch

Updated workflow to build on main branch instead of tags.

Refactor activity filtering

Add --in-memory for quick testing