[MaximumTrainer]

Summary

Closes the last code AC on the epic before the P9/P10 cutover: deletes the React/three.js tree now that the Svelte + WebGPU port is at parity (PRs #581–#586).

Gone: src/App.tsx, src/main.tsx, src/components/*.tsx (29 root-level), src/components/rower3d/*.tsx + their three.js-dependent .ts helpers (71 files total), src/hooks/ (19 React hooks), src/context/ (Auth + Services + their consumers), 66 *.tsx tests + the handful of *.ts tests that only measured a React-era contract. The six parity suites under src/lib/scenery/__tests__/ were pinned to each React implementation, so they go too. The repo-root index.html was only there to boot src/main.tsx — SvelteKit owns the HTML host via src/app.html. Two Playwright specs that read deleted modules (route-performance-budgets, rower-stroke) leave with them; the engine-side equivalents re-land with the GPU-runner work in #548/#584 territory.

Kept (Svelte/src/lib/renderer still import them, as pure TS): routeMapProjection.ts, and under src/components/rower3d/ — conditions, constants, crewModel, ghost, navigableWidth, rowerAppearance, sceneQuality, sceneryAssets, sceneryClearance, sceneryConfig, sceneryCrossings, sceneryRegion, sceneryTrack, segmentScenery, themeConfig. Those relocate into src/lib/ in a later slice.

Config fallout: tsconfig.app.json drops jsx: react-jsx (no .tsx left); tsconfig.playwright.json drops the renderBudget / strokePose includes (and the two spec files that read them); eslint.config.js drops the react-hooks + react-refresh plugins; setupTests.ts drops the @testing-library/jest-dom shim (no surviving test uses its matchers); playwright.config.next.ts drops the two deleted specs from the next-branch testIgnore.

Coverage (second commit on the branch, #542 AC1: re-base coverage floors after the React sweep): removing the React tree is a measurement change on the same shape as #542 P0's Vitest 1 → 3 upgrade. New reading over the surviving tree is 89.11 / 89.11 / 85.77 / 90.66 (lines / statements / branches / functions); floors land a point under each, per the "clear of the measurement" rule the comments in vitest.config.ts have followed since #340. The per-file 100 floors on the deleted scene helpers are dropped; the engine-side tests that take over their measurement re-land with the renderer work they belong to.

Follow-up PR (not this one): package.json dep cleanup — react, react-dom, @react-three/*, postprocessing, react-chartjs-2, @testing-library/react, @react-three/test-renderer, @types/react, @types/react-dom, @vitejs/plugin-react, eslint-plugin-react-hooks, eslint-plugin-react-refresh. Nothing in the surviving tree imports them, but ripping them out touches package-lock.json and deserves its own review.

Local gates all green: tsc, eslint, vitest (213 files · 2081 pass · 8 skip), tsc -p tsconfig.playwright.json, svelte-check (clean modulo pre-existing node_modules esrap + tsconfig composite warnings), vitest --coverage under the re-based thresholds.

Test plan

• Preflight / scaffold smoke / WebGPU engine smoke / e2e shards 1/2 + 2/2 all green on next/svelte-webgpu
• GPU runner smoke stays skipped (gated on GPU_RUNNER_LABEL)
• Verify on Dan's wood-laptop-g5 after merge that npm run dev + npm run build still boot the Svelte app
• Follow-up PR drops the React deps from package.json once this lands

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Generated by Claude Code