[Bug]: [P3] Recycling demand/fill gauges flap during the lunch census dip

Imported from the engineering backlog (_bmad-output/implementation-artifacts/backlog.md, story recycling-census-flap).
Priority P3 (do-first order) | Severity: low | Status: idea | Epic: gameplay-feel | Type: bug | Recorded: 2026-07-12

What happened?

Party decision 2026-07-12 (PR #184 takeover review, from Sally's UX pass). recyclingDemandMet() and recyclingFill() read totalPopulation(), which now swells with live venue customers, so a tower within a knife's edge of exactly 2,500-per-center can flip the 4-star recycling gate at the lunch peak and re-arm the edge-triggered "Garbage is piling up" bulletin daily. Fix candidates: base the recycling gate and nudge on a non-transient census (baseline without customersIn), a daily-peak smoothed value, or debounce the bulletin across a day. Also consider Sally's stats-overview footnote ("Population varies through the day as customers visit venues") which preempts the general "is my POP broken?" question after a star is minted at a lunch peak.

Start by locating recyclingDemandMet(), recyclingFill(), totalPopulation(), and the edge-triggered "Garbage is piling up" bulletin logic. Compare how customersIn affects the recycling gate and nudge during the lunch census dip, then review the listed smoothing, baseline, or debounce candidates. Done means the gauges and bulletin no longer flap across the daily population variation, with the stats-overview footnote handled if that approach is chosen.