T13: Contract - delete Global (wide-refactor expand-contract tail)

[Jon-Gear]

Parent

Restructure spec: #13 (RESTRUCTURE_PLAN.md)

What to build

The contract tail of the wide refactor. Every earlier ticket expanded a new seam beside Global and migrated a subsystem's call sites batch by batch. This ticket removes the Global autoload once no caller remains, sweeps residual references, and runs a full-game verification that behavior is unchanged. Green is promised here, where each batch was kept green by the retained old form.

Acceptance criteria

• Global autoload removed; zero references remain anywhere in the project
• Full flow verified identical: menu to play, hurt, death, respawn, wave advance, game-over
• Test suite green

Blocked by

• T4 Wave and scoring through state and service (T4: Wave and scoring through state and service #17)
• T5 Brothers, combat, and respawn through state and service (T5: Brothers, combat, and respawn through state and service #18)
• T6 Weapon switching and ammo through a service (T6: Weapon switching and ammo through a service #19)
• T7 Fire module for bullets (T7: Fire module for bullets #20)
• T8 FlowController scene flow (T8: FlowController scene flow #21)
• T9 Split-screen behind the brother-facts seam and camera FX (T9: Split-screen behind the brother-facts seam and camera FX #22)
• T10 Data-driven configuration and editor tooling (T10: Data-driven configuration and editor tooling #23)
• T11 External adapters (Newgrounds, save) and secrets hygiene (T11: External adapters (Newgrounds, save) and secrets hygiene #24)
• T12 Collapse duplicated combatant behavior (T12: Collapse duplicated combatant behavior #25)