Add sisyphus

.sisyphus/notepads/rete-rules-engine/learnings.md

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+## [2026-04-16] Session ses_267b9d7a2ffeFkGcPFn1iv223J Start
+
+### Codebase State (Phase 3.8 complete)
+- 323 tests pass, 0 fail across all packages
+- Engine (`packages/rete/src/`): fully implemented — schema, WM, alpha/beta, join, filter, query, derived, negation, existential, NCC, aggregation, event log, snapshot, replay
+- Chess (`packages/chess/src/`): all FIDE rules + 15 presets implemented
+  - Presets in `packages/chess/src/presets/registry.ts`
+  - Fact schema in `packages/chess/src/schema.ts`
+  - Engine facade in `packages/chess/src/engine.ts`
+- Chess package.json already has `vite`, `@vitejs/plugin-react`, `react`, `react-dom`, `@types/react`, `@types/react-dom` in devDeps
+- No `index.html`, no `src/app/`, no UI files yet
+
+### Key Conventions
+- Bun workspaces, `bun test`, NOT npm/node
+- TypeScript strict: `noImplicitAny`, `exactOptionalPropertyTypes`, `noUncheckedIndexedAccess`
+- ESLint flat config in `eslint.config.js`
+- No `as any`, no `@ts-ignore`
+- All tests: Vitest (not Jest)
+- Tailwind for styling (per plan P3.9)
+- React 19
+- Square encoded as number 0..63
+- Pieces as EntityId with multiple attrs
+
+### Chess Architecture
+- `Session` from `@paratype/rete` — the game engine
+- `generateStartingPosition(session)` — inserts 32 piece facts
+- `AttemptedMove` fact = move intent
+- `LegalMove` derived fact = legal moves per piece
+- `InCheck`, `GameOver` derived facts
+- Presets: PRESET_REGISTRY in `packages/chess/src/presets/registry.ts`
+- `engine.ts` — higher-level facade wrapping Session
+
+### UI Requirements (P3.9-P3.15)
+- Routes: Home (/), Game (/game), Rules (/rules), Save (/save)
+- Board: `[data-square="e2"]`, `[data-piece="white-pawn"]` selectors needed for Playwright
+- Drag-drop: HTML5 DnD or react-dnd
+- `[data-action="undo"]`, `[data-action="save"]`, `[data-action="export"]`, `[data-action="import"]`
+- `[data-testid="app-root"]` on root element
+- `[data-preset="{id}"] [data-role="toggle"]`
+- localStorage key: `paratype-chess:v1:autosave`