explore: pivot to noclip free-roam camera

Ground-truth from render_overworld.py showed Kanto is ONE seamless world joined
along shared edges with per-connection offsets -- so a map-by-map browser is the
wrong model. Replaced it with noclip free-roam that leans on the engine's own
player-walk + connection-crossing machinery (which already handles seams/offsets
correctly):

- wSlopNoclip flag (reused the dead wUnusedObtainedBadges byte at D356, 0 r/w,
  not unioned, in the saved region -> safe).
- CollisionCheckOnLand: 5-byte hook at the top -> when noclip is set, return
  no-collision. Freed the room in ROM0 by deleting the unreferenced Func_0db5
  (dead farcall LoadToggleableObjectData) in LoadMapHeader.
- EXPLORE menu entry now just toggles wSlopNoclip and closes the menu, dropping
  you into the overworld to glide through walls/NPCs/ledges and walk across map
  connections exactly as the world data defines them.

Verified: Pallet -> (walk north through the fences) -> seam-cross into Route 1 at
y=35 -> continue north; toggle off restores collision (player blocked).

0 files changed, 0 insertions, 0 deletions