fix: override app.currentContext type define (#5578)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Added an application-level getter to access the current request
context outside typical handlers.

* **Tests**
* Removed TypeScript type-checking test suites for application and
plugin APIs.

* **Chores**
* Updated dev dependency versions for Node types, Mocha, and TypeScript.
  * Removed an unused type-testing tool from the workspace and packages.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: fengmk2

packages/egg/package.json

@@ -166,7 +166,6 @@
     "runscript": "catalog:",
     "sdk-base": "catalog:",
     "spy": "catalog:",
-    "tsd": "catalog:",
     "tsdown": "catalog:",
     "typescript": "catalog:"
   },

packages/egg/src/lib/egg.ts

@@ -73,6 +73,16 @@ export { Context, Router };
  */
 export class EggApplicationCore extends EggCore {
   declare ctxStorage: AsyncLocalStorage<Context>;
+
+  /**
+   * Get the current request context from AsyncLocalStorage.
+   * This provides access to the context object for the current request lifecycle.
+   * @returns {Context | undefined} The current request context, or undefined if not in a request scope.
+   */
+  get currentContext() {
+    return this.ctxStorage.getStore();
+  }
+
   // export context base classes, let framework can impl sub class and over context extend easily.
   ContextCookies = ContextCookies;
   ContextLogger = ContextLogger;

packages/egg/test/index.test-d.ts

@@ -125,7 +125,6 @@
     "@eggjs/tegg-plugin": "catalog:",
     "@types/methods": "catalog:",
     "egg-errors": "catalog:",
-    "tsd": "catalog:",
     "tsdown": "catalog:",
     "typescript": "catalog:"
   },