feat(game): choose a game mode before entering the yard

[ralyodio]

/play only ever opened one scene — Team Deathmatch against bots — with no way to see or change that. It now asks first.

Mode	What's in the yard
Team Deathmatch	Four Directorate against you and three Nightcell. They flank, shoot back and throw.
Firing Range	Stationary targets. Nothing returns fire — for learning the rifle and the grenade arc.
Free Roam	The yard, empty.

Two of the three already existed and had no entry point. TrainingTargets and the empty greybox are the "training" and "greybox" technical scenes PRD §23.1 already lists under the free sandbox. This exposes built work rather than adding scope.

Not new competitive modes

The locked V1 decision is one multiplayer mode — 6v6 Team Deathmatch — and inventing a second would contradict it. Everything here is single-player against NPCs and sits on the free side of the access line, so /play stays openable without an account. Worth saying plainly since the request started from "can we have a multiplayer demo": this is NPCs only, no networked play.

Notes

• Opponents now takes a roster size, and an empty roster is a supported configuration, not a degenerate one: it owns the MatchSimulation, which is where the player's own grenade count, cooldown and blast are resolved, so it is built in every mode including the ones with no bots.
• The picker is a real fieldset/radio group, so arrow-key navigation and screen-reader announcement come for free (accessibility is P0). The native input is visually hidden but keeps focus, so the focus ring is drawn on the label — without that the group is keyboard-navigable and invisible to anyone using it that way.
• Changing mode reloads rather than re-dressing the yard live: roster and targets are decided at boot, and swapping them in place would be a second, subtly different code path for something that happens once.
• The choice is remembered on change, not on start, so picking a mode and then reloading does not silently lose it. ?mode= beats the remembered value so a shared link opens what it says.
• ?mode= is also read by access.ts for demo/campaign/multiplayer. The two never collide — access values are not scene ids and fall through to the default — and there is a test pinning exactly that.

Verification

Typecheck, lint, 245 tests (10 new) and the build pass. All three modes were booted in a browser and screenshotted: the picker renders with the selected mode highlighted and its blurb below, Firing Range spawns stationary targets with no roaming bots, and Free Roam is empty. No console errors in any of the three.

🤖 Generated with Claude Code

[github-actions]

vu1nz Security Review

0 finding(s) in PR #?

No security issues found.