Issue #695: Pressing B in PC submenus (BoxMenu, PlayerPC) was exiting
the entire PC session instead of returning to the main PC menu. The
three main-menu items (Bill's PC, player's PC, Prof. Oak's PC) were
missing keepOpen=true, so selecting one popped the main menu off the
stack. Added keepOpen to all three, matching the pattern already used
by BoxMenu and PlayerPC's own rows.
Issue #694: Falling through boulder holes in Seafoam Islands, Victory
Road, and Pokemon Mansion played no sound effect. Added Faint_Fall sfx
before every hole warp -- the scripted onStep holes in seafoam.lua,
story.lua, and story6.lua, plus the warp-tile-based hole detection in
OverworldController takeWarp. Faint_Fall is the companion to Faint_Thud
(already played when boulders fall into holes).
Fixes#695Fixes#694