New /bulk-log page: paste emails (semicolon/comma/newline separated), choose
method, outcome, contact date and a follow-up date, review the matches, then
log the contact on every matching non-removed business. Reuses
BusinessRepository.LogInteraction so status and next-contact date update the
same way as the single-business form.

Registers bulklogcontroller in the core controller whitelist.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>