feat(display): host companion controls in Presentation

[papi-ux]

Summary

• replace the external-display companion Activity with a Game-owned Presentation
• place companion controls on the explicitly requested display while preserving stream launch routing
• retain both public static JVM focus entry points for Java callers
• clean up the Presentation with the owning Game lifecycle

Compatibility and safety

• keeps requestFocusToExternalDisplayControl(Context) and requestFocusToExternalDisplayControl(Context, int) as @JvmStatic APIs
• removes the companion Activity declaration and avoids focusable overlay/window behavior
• preserves explicit display selection through receiver and trampoline paths
• physical Thor verification remains a final validation gate; local JVM evidence is not presented as physical-device proof

Test plan

• :app:testRootDebugUnitTest — 762/762
• :app:testNonRoot_gameDebugUnitTest — 756/756
• reflected both public static JVM overloads with correct reference/primitive parameter types
• deletion mutation for the Context-only overload fails the compatibility test
• independent production/runtime review PASS
• independent compatibility test-contract review PASS

Refs #127