chore: 删除不再需要的示例包和工具配置

移除pkg-a、pkg-b和tooling-config包及其相关文件，这些是用于演示的示例代码

packages/pkg-a/README.md

@@ -1 +0,0 @@
-Change me to miss cache!

packages/pkg-a/package.json

@@ -1,11 +0,0 @@
-{
-  "name": "pkg-a",
-  "scripts": {
-    "build": "echo \"Building at the speed of Turbo.\" > output-file.txt && cat output-file.txt",
-    "lint": "echo \"Linted!\"",
-    "check-types": "echo \"Types checked!\""
-  },
-  "dependencies": {
-    "tooling-config": "workspace:*"
-  }
-}

packages/pkg-b/README.md

@@ -1 +0,0 @@
-Change me to miss cache!

packages/pkg-b/package.json

@@ -1,11 +0,0 @@
-{
-  "name": "pkg-b",
-  "scripts": {
-    "prebuild": "echo \"Executing pre-build step...\"",
-    "build": "echo \"Welcome to the Turboverse.\" > output-file.txt && cat output-file.txt",
-    "check-types": "echo \"Types checked!\""
-  },
-  "dependencies": {
-    "tooling-config": "workspace:*"
-  }
-}

packages/tooling-config/README.md

@@ -1 +0,0 @@
-Because this package is shared in every package in the monorepo, a source code change in this package will cause a cache miss for all tasks in all packages.

packages/tooling-config/package.json

@@ -1,4 +0,0 @@
-{
-  "name": "tooling-config",
-  "description": "A package used by every other package."
-}