fix(tests): handle unknown .jsx extension for TanStack solid dependencies (@ennajari) (#7806)

Fixes #7801

`@tanstack/solid-*` packages ship `.jsx` source files that Node.js
cannot load without a JSX transform.

**Fix:** Add `ssr.noExternal: ["@solidjs/meta", /@TanStack\/solid-.*/]`
to all three test projects (unit, jsdom, jsx). This forces Vite to
bundle and transform them through `vite-plugin-solid`.

**Test plan**
- pnpm vitest run completes without "Unknown file extension" errors
- Tests importing `@tanstack/solid-*` packages run correctly

Author: ennajari

frontend/vitest.config.ts

@@ -9,8 +9,16 @@ const plugins = [
   solidPlugin({ hot: false }),
 ];
 
+const tanstackSolidNoExternal: (string | RegExp)[] = [
+  "@solidjs/meta",
+  /@tanstack\/solid-.*/,
+];
+
 export const projects: UserWorkspaceConfig[] = [
   {
+    ssr: {
+      noExternal: tanstackSolidNoExternal,
+    },
     test: {
       name: { label: "unit", color: "blue" },
       include: ["__tests__/**/*.spec.ts"],
@@ -26,6 +34,9 @@ export const projects: UserWorkspaceConfig[] = [
     plugins,
   },
   {
+    ssr: {
+      noExternal: tanstackSolidNoExternal,
+    },
     test: {
       name: { label: "jsdom", color: "yellow" },
       include: ["__tests__/**/*.jsdom-spec.ts"],
@@ -36,7 +47,7 @@ export const projects: UserWorkspaceConfig[] = [
   },
   {
     ssr: {
-      noExternal: ["@solidjs/meta"],
+      noExternal: tanstackSolidNoExternal,
     },
     test: {
       name: { label: "jsx", color: "green" },