git-recon: mass multiplayer (many players in one repo battle) #1172

git-recon is single-player today (world: false, guards are bots). The goal is mass multiplayer: lots of players fighting through the same repo at once, arena-shooter style, with the toy-soldier squad combat on top.

A sketch to scope before building:

• Room per level + repo. One authoritative room per (level, owner/repo@ref), e.g. a Durable Object per room. Game in src/sim/game.ts already runs headless in fixed 120 Hz ticks, so the server can run it as is.
• Netcode. Clients send Input each tick. The server steps Game and broadcasts snapshots at ~20 Hz. Clients predict their own soldier and interpolate everyone else. Shots are server-authoritative, with lag-compensated hit checks using each soldier's existing trail.
• Teams and modes. Players on two sides (ours vs theirs, or one branch vs another) plus the bot guards. Free-for-all, team deathmatch, and the existing missions (carry the commit, hold main) as objective modes.
• Scale. Start with 16–32 per room, then measure. Snapshot deltas and interest management (only soldiers near you) come before pushing the count higher.
• Cost. Price the Durable Object and bandwidth before any live deploy, and keep the first one the smallest live resource.

The shield, hit arcs and blended poses from the graphics pass already work per soldier, so remote players get them for free.