Ban/Unban actions should maintain history and track who performed the action

Currently, when a volunteer is banned or unbanned from a program, the history of those actions is not preserved. This makes it difficult to determine whether a volunteer has previously been banned, why the action occurred, and who performed it.

Expected Behavior / What Should Be Added

The system should maintain a permanent history of all volunteer ban and unban actions. Each time a volunteer is banned or unbanned, a new history record should be created that captures the volunteers name, program name, action type (Ban or Unban), the reason for the action, the user who performed the action, and the date and time the action occurred. This history should remain accessible and should not be overwritten or deleted when a volunteer's status changes, allowing users to review past ban and unban activity and determine whether a volunteer has a history of eligibility related actions.

The issue does not name files or tests. Start by locating the volunteer ban and unban entry points, then trace the existing volunteer status data and persistence flow. Define the history record around the volunteer, program, action, reason, actor, and timestamp; done means every ban or unban is retained and reviewable without overwriting earlier actions.

Written by the indexing model from the issue text.