Ship agent docs with the packages, and check simulation lint coverage

[SandroMaglione]

A game's coding agent only sees what npm installs. This PR makes that its complete source of truth, makes the root README the only doc for humans, and closes the fail-open gap in the simulation lint rules.

For game agents (all shipped in the packages)

• SETUP.md (in @typeonce/ritmo): one-time setup. Base packages and checks for every game (ritmo, ritmo-math, ritmo-devtools, oxlint-plugin-ritmo, oxlint), add-ons only when needed (ritmo-browser, ritmo-render, ritmo-pixi), linking the skill, .oxlintrc.json, a ritmo-devtools lint entry, and one check script.
• skills/ritmo/SKILL.md: for every change. Where the docs are (source JSDoc, READMEs, changelogs), principles for where code and state belong, and a self-check. It doesn't repeat anything JSDoc, READMEs or lint messages already say.
• Changelogs: every package ships its CHANGELOG.md. The 0.8.0 and 0.9.0 upgrade notes moved into the core changelog. MIGRATION.md keeps only the bevy-ts rename, which the published npm deprecation messages link to.
• JSDoc fixes:
  • the Command example compiles;
  • examples no longer provide Math.random or performance.now() as services;
  • inspector docs match the actual behaviour;
  • every example name is prefixed;
  • the remaining CONCEPTS.md and GAME_API.md guidance moved into JSDoc.
• Package README links point at GitHub, so they work from npm.

ritmo-devtools lint: uncovered-simulation-module

• What it reports: every module that importing the entry loads, inside the .oxlintrc.json directory and outside node_modules, where ritmo/keep-simulation-headless is not on. Overrides apply in order, last match wins, and ignorePatterns counts as uncovered. The command exits 1 when anything is reported.
• What it skips: modules imported inside lintTarget, such as render schedules passed to describe, are host code and not checked.
• When it doesn't run: with no config, a config using extends, or no simulation override, it prints why the check didn't run and does not fail.
• Node: requires Node 22.15 or newer (engines.node).

For humans

• Root README: pitch, quick start, packages, guarantees, and a starter prompt that links SETUP.md.
• Deleted: CONCEPTS.md, GAME_API.md, PLATFORM.md (its rules are folded into AGENTS.md), the example READMEs, and the superseded recipes example.
• AGENTS.md: a new Docs section records which reader gets which doc.

Verification

• pnpm run check and pnpm pack:check pass. pack:check now asserts that CHANGELOG.md, SETUP.md and the skill are in the tarballs.
• Pre-release trial:
  • Setup: tarballs packed from this branch and served through pnpm overrides; empty scratch projects outside the repo; only the README starter prompt plus one game sentence.
  • Agents: Opus 5.5 Medium and GPT-6.1-Sol Medium.
  • Result: both completed setup, linked the skill, built the game with Clock, seeded Random, InputCapture and FixedLoop, wrote headless tests including Determinism.check, and passed their own pnpm check.
  • Coverage check: on one generated project, importing an uncovered module was reported and the command exited 1.

Follow-up

Running the new check against examples/top-down finds modules the repo's own .oxlintrc.json doesn't cover.

🤖 Generated with Claude Code