feat(plugin-sdk): add TypeScript SDK for Infinite Canvas plugins with automatic JSX and build support

plugins/canvas/sdk/package.json

@@ -0,0 +1,24 @@
+{
+    "name": "@infinite-canvas/plugin-sdk",
+    "version": "0.1.0",
+    "private": true,
+    "type": "module",
+    "description": "Infinite Canvas 画布节点插件 SDK:类型、automatic JSX 运行时、构建助手",
+    "exports": {
+        ".": "./src/index.ts",
+        "./jsx-runtime": "./src/jsx-runtime.ts",
+        "./jsx-dev-runtime": "./src/jsx-dev-runtime.ts",
+        "./build": "./build.mjs"
+    },
+    "scripts": {
+        "typecheck": "tsc --noEmit"
+    },
+    "peerDependencies": {
+        "@types/react": ">=18"
+    },
+    "devDependencies": {
+        "@types/react": "19.1.12",
+        "esbuild": "^0.25.0",
+        "typescript": "^5"
+    }
+}