fix: replace MSYS cat with cross-platform read-stdin tool in stdin tests

MSYS cat from Git for Windows crashes with MapViewOfFileEx errors when
stdin is set to Stdio::null(), causing CI failures on Windows. Replace
with a Node.js read-stdin tool that handles null stdin gracefully.

Author: branchseer

crates/vite_task_bin/tests/e2e_snapshots/fixtures/stdin-inheritance/packages/other/package.json

@@ -1,6 +1,6 @@
 {
   "name": "other",
   "scripts": {
-    "read-stdin": "cat"
+    "read-stdin": "read-stdin"
   }
 }

crates/vite_task_bin/tests/e2e_snapshots/fixtures/stdin-inheritance/snapshots/multiple tasks get null stdin.snap

@@ -3,9 +3,9 @@ source: crates/vite_task_bin/tests/e2e_snapshots/main.rs
 expression: e2e_outputs
 ---
 > echo from-stdin | vp run -r read-stdin
-$ cat ⊘ cache disabled: no cache config
+$ read-stdin ⊘ cache disabled: no cache config
 
-~/packages/other$ cat
+~/packages/other$ read-stdin
 
 
 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
@@ -17,9 +17,9 @@ Performance:  0% cache hit rate
 
 Task Details:
 ────────────────────────────────────────────────
-  [1] stdin-inheritance-test#read-stdin: $ cat ✓
+  [1] stdin-inheritance-test#read-stdin: $ read-stdin ✓
       → Cache disabled in task configuration
   ·······················································
-  [2] other#read-stdin: ~/packages/other$ cat ✓
+  [2] other#read-stdin: ~/packages/other$ read-stdin ✓
       → Cache miss: no previous cache entry found
 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

crates/vite_task_bin/tests/e2e_snapshots/fixtures/stdin-inheritance/snapshots/single task no cache inherits stdin.snap

@@ -3,7 +3,7 @@ source: crates/vite_task_bin/tests/e2e_snapshots/main.rs
 expression: e2e_outputs
 ---
 > echo from-stdin | vp run read-stdin
-$ cat ⊘ cache disabled: no cache config
+$ read-stdin ⊘ cache disabled: no cache config
 from-stdin
 
 
@@ -16,6 +16,6 @@ Performance:  0% cache hit rate
 
 Task Details:
 ────────────────────────────────────────────────
-  [1] stdin-inheritance-test#read-stdin: $ cat ✓
+  [1] stdin-inheritance-test#read-stdin: $ read-stdin ✓
       → Cache disabled in task configuration
 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

crates/vite_task_bin/tests/e2e_snapshots/fixtures/stdin-inheritance/snapshots/single task with cache gets null stdin.snap

@@ -3,7 +3,7 @@ source: crates/vite_task_bin/tests/e2e_snapshots/main.rs
 expression: e2e_outputs
 ---
 > echo from-stdin | vp run read-stdin-cached
-$ cat
+$ read-stdin
 
 
 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
@@ -15,6 +15,6 @@ Performance:  0% cache hit rate
 
 Task Details:
 ────────────────────────────────────────────────
-  [1] stdin-inheritance-test#read-stdin-cached: $ cat ✓
+  [1] stdin-inheritance-test#read-stdin-cached: $ read-stdin ✓
       → Cache miss: no previous cache entry found
 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

crates/vite_task_bin/tests/e2e_snapshots/fixtures/stdin-inheritance/vite-task.json

@@ -2,11 +2,11 @@
   "cacheScripts": true,
   "tasks": {
     "read-stdin": {
-      "command": "cat",
+      "command": "read-stdin",
       "cache": false
     },
     "read-stdin-cached": {
-      "command": "cat",
+      "command": "read-stdin",
       "cache": true
     }
   }

packages/tools/package.json

@@ -7,6 +7,7 @@
     "print-file": "./src/print-file.ts",
     "print-env": "./src/print-env.js",
     "json-edit": "./src/json-edit.ts",
+    "read-stdin": "./src/read-stdin.js",
     "replace-file-content": "./src/replace-file-content.ts"
   },
   "dependencies": {

packages/tools/src/read-stdin.js

@@ -0,0 +1,6 @@
+#!/usr/bin/env node
+
+// Cross-platform cat replacement: reads all of stdin and writes it to stdout.
+// Unlike MSYS cat on Windows, this handles Stdio::null() gracefully by
+// receiving an immediate EOF rather than crashing.
+process.stdin.pipe(process.stdout);