# Tasks: enterprise-gaming-vehicle-physics

## 0. Pre-flight (non-negotiable)

- [ ] 0.1 Confirm clean working tree (`git status` reports nothing) and no in-flight worktrees with uncommitted work (`git worktree list` then `git status` in each)
- [ ] 0.2 If any worktrees exist under `.claude/worktrees/`, account for each one: still-active agent, work-pending-merge, or stale-and-prune. Stale worktrees MUST be removed (`git worktree remove`) before opening a new one — code that has been lost twice on main is the failure mode this guards against.
- [ ] 0.3 Confirm the package set in `MANIFEST.md` matches `find packages -maxdepth 3 -name package.json` count. Drift here means a prior change archived without regenerating the manifest.

## Phase 1 — Scaffold

- [ ] Create `gaming/rigs/vehicle-physics/` (`@suaveplan/vehicle-physics`, `0.1.0`, `sideEffects: false`)
- [ ] `tsconfig.json`, `vitest.config.ts`

## Phase 2 — Error codes & constants

- [ ] `src/error-codes.ts` + `src/constants/index.ts` (air density, default torque curve, shift thresholds)

## Phase 3 — Types

- [ ] `src/types/common.ts` + `common.md`

## Phase 4 — Pacejka tire model

- [ ] `src/models/pacejka/pacejka.ts` — lateral force + longitudinal force from slip angle/ratio + BCDE coefficients
- [ ] Tests: symmetry at zero slip, force direction
- [ ] Docs

## Phase 5 — Suspension

- [ ] `src/models/suspension/suspension.ts` — spring-damper PD controller per wheel, compression ratio
- [ ] Tests + docs

## Phase 6 — Drivetrain

- [ ] `src/models/drivetrain/drivetrain.ts` — torque distribution FWD/RWD/AWD, gear ratio, differential slip, auto-shift
- [ ] Tests + docs

## Phase 7 — Null backend

- [ ] `src/backends/null-backend/null-backend.ts` — flat infinite ground; all wheels grounded
- [ ] Tests + docs

## Phase 8 — Vehicle

- [ ] `src/core/vehicle/vehicle.ts` — integrate all models per tick, OTel, events
- [ ] Tests + docs

## Phase 9 — Property tests

- [ ] `tests/property.test.ts` — tire symmetry, suspension convergence, throttle → speed monotone

## Phase 10 — Pre-publish gate

- [ ] `bunx turbo lint typecheck test --filter=@suaveplan/vehicle-physics` green
- [ ] 100% coverage
- [ ] Publish: `bun scripts/publish.ts --package @suaveplan/vehicle-physics`