[M1-S4] Drop through one-way platforms and climb ladders #30

User story

As a player, I want to jump up through girder decks, drop down through them and climb ladders, so that I can move up and down the rust maze.

Acceptance criteria

• Stand on yellow lines, jump up through them, ↓ + Jump drops
• ↑ in a blue climb zone climbs ladders, vines, scaffold; slow; no attacking while climbing
• No ledge pull-up (cut in A14)

Design and references

02 – Movement.

Dependencies

Needs the collision loader. Suggested owner: Vatsal (player and combat code).

Verification

Climb every ladder on the Rusty Creek route up and down; drop through each deck.