Port upstream PR #329: hide CLI console window on Windows

Add explicit PIPE redirect configuration to ProcessBuilder in spawn-cli,
ensuring the JVM sets CREATE_NO_WINDOW on Windows. This prevents a
console window from appearing when spawning the CLI from GUI applications.

The JVM's ProcessImpl already uses CREATE_NO_WINDOW when all stdio handles
are pipes (not inherited from parent console). Making the PIPE redirects
explicit documents this intent and protects against regressions.

Co-authored-by: krukow <3635+krukow@users.noreply.github.com>

Author: Copilot

CHANGELOG.md

@@ -3,6 +3,9 @@ All notable changes to this project will be documented in this file. This change
 
 ## [Unreleased]
 
+### Added (upstream PR #329 sync)
+- Windows console window hiding: CLI process is spawned with explicit PIPE redirects ensuring the JVM sets `CREATE_NO_WINDOW` on Windows — no console window appears in GUI applications. Equivalent to upstream `windowsHide: true` (upstream PR #329).
+
 ### Changed
 - Recommended default model for non-streaming examples is `claude-haiku-4.5` instead of `gpt-5.2` for faster response times
 

src/github/copilot_sdk/process.clj

@@ -68,7 +68,14 @@
       (when github-token
         (.put env-map "COPILOT_SDK_AUTH_TOKEN" github-token)))
 
-    ;; Configure stdio
+    ;; Configure stdio — use explicit PIPE redirects for all three streams.
+    ;; On Windows, the JVM's ProcessImpl sets CREATE_NO_WINDOW when none of the
+    ;; child's stdio handles are inherited from the parent console. By ensuring
+    ;; PIPE (not INHERIT) for stdin, stdout, and stderr, we guarantee no
+    ;; console window appears — equivalent to upstream windowsHide: true (PR #329).
+    (.redirectInput builder ProcessBuilder$Redirect/PIPE)
+    (.redirectOutput builder ProcessBuilder$Redirect/PIPE)
+    (.redirectError builder ProcessBuilder$Redirect/PIPE)
     (.redirectErrorStream builder false)
 
     (let [process (.start builder)