Mythic Masters: orbit-and-commit combat, weighty attacks (parallel round) #2945

Part of #2802. Parallel to the art hill climb in #2943.

The goal (owner's words, tidied)

Fights should be less about running in circles at each other and more about weighty, committed melee. The owner is happy to circle: the fighter orbits the opponent, and the opponent can switch circle direction, but the two never stand and face each other down in a straight line. Attacks should feel heavy, in the way of a slow stamina-gated action game: a wind-up you commit to, a hit that lands with weight, a recovery you can be punished in.

Feel targets

1. Orbit, don't charge. Movement is circling the opponent (strafe on a ring around them, forward/back to close or open the gap). The camera frames both. No straight head-on standoff.
2. Committed attacks. Longer, readable wind-ups on heavy moves, no cancelling out of an attack, real recovery frames that leave you open. Light moves stay quick but still commit.
3. Stamina is the limit. Every swing and dash costs stamina; running dry leaves you open. Guarding and dodging cost it too.
4. Weight you can see. Bodies drop their weight into a swing, hits stop the world for a beat, big hits stagger and push the other beast back, the camera gives a small shove.
5. Opponent that fights this way. The bot circles, switches direction now and then, baits a swing and punishes the recovery. It doesn't mirror you in a straight line.

Workers (all from main, one PR each, never stacked; Mervin settles overlap in sim.ts)

Run bun run tune 800 for bot balance and keep the suite green. Check a fight in the running app (?a=..&b=..&skin=..&watch=1) before opening the PR.

Rules

• No names of commercial games anywhere (code, docs, commits, PRs, issues): say "weighty stamina-based melee".
• Each PR says "Part of #N", not a closing word, until the owner agrees the feel is right.
• Check in with the owner after each worker's first PR: this is a feel change and needs hands on a controller.