fix(server): restore original request.emit method in Node Body Limit Plugin (#863)

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

## Summary by CodeRabbit

* **Bug Fixes**
* More accurate enforcement of maximum request body size, leveraging
Content-Length when available.
* Consistent 413 Payload Too Large errors without duplicate or premature
checks.
  * Prevents over-reading by tracking streamed body size per chunk.

* **Refactor**
* Improved stability of request event handling during and after
middleware execution, ensuring original behavior is restored.
* Streamlined internal flow to perform size checks once and maintain
reliable processing of incoming requests.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Author: dinwwwh

packages/server/src/adapters/node/body-limit-plugin.ts

@@ -2,6 +2,7 @@ import type { Context } from '../../context'
 import type { NodeHttpHandlerOptions } from './handler'
 import type { NodeHttpHandlerPlugin } from './plugin'
 import { ORPCError } from '@orpc/client'
+import { once } from '@orpc/shared'
 
 export interface BodyLimitPluginOptions {
   /**
@@ -26,17 +27,13 @@ export class BodyLimitPlugin<T extends Context> implements NodeHttpHandlerPlugin
     options.adapterInterceptors ??= []
 
     options.adapterInterceptors.push(async (options) => {
-      let isHeaderChecked = false
-
-      const checkHeader = () => {
-        if (!isHeaderChecked && Number(options.request.headers['content-length']) > this.maxBodySize) {
+      const checkHeader = once(() => {
+        if (Number(options.request.headers['content-length']) > this.maxBodySize) {
           throw new ORPCError('PAYLOAD_TOO_LARGE')
         }
+      })
 
-        isHeaderChecked = true
-      }
-
-      const originalEmit = options.request.emit.bind(options.request)
+      const originalEmit = options.request.emit
 
       let currentBodySize = 0
 
@@ -51,10 +48,15 @@ export class BodyLimitPlugin<T extends Context> implements NodeHttpHandlerPlugin
           }
         }
 
-        return originalEmit(event, ...args)
+        return originalEmit.call(options.request, event, ...args)
       }
 
-      return options.next()
+      try {
+        return await options.next(options)
+      }
+      finally {
+        options.request.emit = originalEmit
+      }
     })
   }
 }