feat(core): share API request assembly between both transports

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

packages/dev-server/src/runtime.ts

@@ -10,6 +10,7 @@ import { brotliCompressSync, constants as zlibConstants } from "node:zlib";
 
 import {
   bridgeRealtime,
+  buildApiRequest,
   createContext,
   createCorsPreflightResponse,
   createRealtimeRegistry,
@@ -1454,7 +1455,12 @@ export function createHandlers(deps: RuntimeDeps): Handlers {
     }
   }
 
-  async function callApiFromContext(ctx: Context, path: string, method = "GET"): Promise<unknown> {
+  async function callApiFromContext(
+    ctx: Context,
+    path: string,
+    method = "GET",
+    input?: Record<string, unknown>,
+  ): Promise<unknown> {
     if (!isSafeApiPath(path)) {
       throw new Error("Unsafe framework API path");
     }
@@ -1464,10 +1470,15 @@ export function createHandlers(deps: RuntimeDeps): Handlers {
       throw new Error(`Unsupported framework API method: ${normalizedMethod}`);
     }
 
-    const apiUrl = new URL(path, ctx.req.url);
+    const built = buildApiRequest(path, normalizedMethod, input);
+    const apiUrl = new URL(built.url, ctx.req.url);
+    const headers = new Headers(ctx.req.headers);
+    if (built.contentType) headers.set("content-type", built.contentType);
+
     const apiReq = new Request(apiUrl, {
       method: normalizedMethod,
-      headers: ctx.req.headers,
+      headers,
+      ...(built.body === undefined ? {} : { body: built.body }),
     });
     const apiCtx = createContext(apiReq, apiUrl);
     apiCtx.locals = ctx.locals;