refactor: workspace restructure — contract package + pure domain ported, tests green

- bun workspaces: contract/ (Schemas = source of truth: config raw↔resolved,
  domain DTOs, HttpApi contract, API errors) + plugin/ + ui/
- pure domain moved src/{engine,art}→plugin/src/{domain,art}, types now
  imported from @rom-manager/contract and @punktfunk/plugin-kit/wire (the
  hand-copied wire.ts dies), loggers injected instead of module-global
- ui.* and devEntry dropped from the config shape (standalone server is
  gone; stale keys tolerated on decode, dropped by the next save)
- all 48 domain tests ported and green BEFORE any Effect wiring

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

contract/package.json

@@ -0,0 +1,25 @@
+{
+	"name": "@rom-manager/contract",
+	"version": "0.0.0",
+	"private": true,
+	"type": "module",
+	"description": "The single source of truth shared by the plugin server and the UI: config schema, domain DTOs, the HttpApi contract, and API errors. Never published — bundled into the plugin, aliased into the UI.",
+	"main": "./src/index.ts",
+	"types": "./src/index.ts",
+	"exports": {
+		".": "./src/index.ts"
+	},
+	"scripts": {
+		"typecheck": "tsc --noEmit"
+	},
+	"peerDependencies": {
+		"effect": "^4.0.0-beta.99",
+		"@punktfunk/plugin-kit": "^0.1.1"
+	},
+	"devDependencies": {
+		"effect": "4.0.0-beta.99",
+		"@punktfunk/plugin-kit": "^0.1.1",
+		"typescript": "^5.9.3",
+		"@types/bun": "^1.3.0"
+	}
+}