Placer.ai foot-traffic audiences

Add a **venue** in the Audiences tab and Campaigns pulls foot-traffic aggregates — year-over-year trend and a resident-vs-visitor split. This is the early-warning signal for downtown business/resident flight: a declining trend is your cue to launch a re-engagement campaign before the tax base erodes.

Foot-traffic uses a provider behind `system_secrets/placer`. Until a key is configured it shows a realistic sample trend (a gentle decline) so the workflow is demonstrable.