[Feature]: [P2] Elevator scheduling parity epic (per-day-type schedules + TDT round-trip)

Imported from the engineering backlog (_bmad-output/implementation-artifacts/backlog.md, story elevator-scheduling).
Priority P2 (do-first order) | Severity: n/a | Status: idea | Epic: Classic parity | Type: feature-request | Recorded: 2026-07-08

Problem / motivation

Gated: tier-2, spec-first (epic). Spec seed: gdd-classic-modern-pricing-roadmap-2026-07-08 §4 + §7. OWNER TIEBREAK 2026-07-08: FULL PARITY. 1994 shipped elevator per-day-type car scheduling (the per-shaft schedule block in the TDT elevator record, docs/canon/tdt-format.md); this was previously listed under "do NOT build" and is now a confirmed Classic parity gap. Build the scheduling behavior AND its UI to match 1994, and round-trip the TDT schedule bytes on import/export (tdtImport.ts/tdtExport.ts currently zero/skip them). Epic-sized: needs its own gdd-/arch- docs before any build (the per-shaft per-day-type schedule model, the editor UI, and how a user schedule interacts with our automatic SCAN dispatch). The 3-day-week/12-day-calendar item stays ratified-out (never part of this conflict). Supersedes the earlier "do NOT build" ruling on this item.

Start with docs/canon/tdt-format.md and the referenced gdd-classic-modern-pricing-roadmap-2026-07-08 sections, then inspect tdtImport.ts and tdtExport.ts to understand the schedule bytes currently skipped or zeroed. Define the per-shaft, per-day-type model, editor UI, and interaction with automatic SCAN dispatch in the required gdd-/arch- documents before implementation. Done includes matching 1994 scheduling behavior and UI plus TDT import/export round-tripping.