Operator-chosen tent pressure: a slider for the target regime (positive / neutral / negative) and how strong the pressure difference should be, per tent or syst

OPERATOR-RAISED 2026-09-14, building on PR #240 (mass_balance_ok is now signed: exhaust-dominant is fine, only over-pressure beyond a fixed tolerance is a fault). The operator wants the pressure intent to be a setting instead of a hard-coded assumption: a slider with visible values where the grower chooses the pressure type (positive, neutral or negative) and how severe the intake-vs-exhaust difference should be. Whether it is offered per tent or system-wide depends on the ducting (a tent whose intake and exhaust are its own vs a shared room lung). Today the target is implicit: expected negative pressure with a tolerance of max(5 CFM, 5 % of the larger side), system-wide. Scope question for the operator before build: is the setting only the target the brain judges against (mass balance / air path read ‘on target / too weak / too strong’), or should it also steer the fans toward it (a live control change on the grow)?