fix: suppress console windows in headless mode

- Launcher: pass CREATE_NO_WINDOW | CREATE_SUSPENDED when creating
WA.exe in headless mode, plus SW_HIDE in STARTUPINFO
- Test runner: use CREATE_NO_WINDOW when spawning launcher
- run-tests.ps1: build test runner then run binary directly

Console/terminal windows no longer appear during headless tests.
WA's own "Loading" GUI dialog still flashes briefly (suppressing it
via ShowWindow hook causes WA to hang or throttle).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

crates/openwa-launcher/src/main.rs

@@ -52,6 +52,7 @@ struct PROCESS_INFORMATION {
 }
 
 const CREATE_SUSPENDED: DWORD = 0x0000_0004;
+const CREATE_NO_WINDOW: DWORD = 0x0800_0000;
 const STARTF_USESHOWWINDOW: DWORD = 0x0000_0001;
 const SW_HIDE: u16 = 0;
 const SW_SHOWMINIMIZED: u16 = 2;
@@ -160,9 +161,14 @@ unsafe fn launch(
     let mut cmdline_buf: Vec<u8> = cmdline.bytes().chain(std::iter::once(0u8)).collect();
     let wd_cstr = path_to_cstring(working_dir)?;
 
+    let headless = std::env::var("OPENWA_HEADLESS").is_ok();
+
     let mut si: STARTUPINFOA = mem::zeroed();
     si.cb = mem::size_of::<STARTUPINFOA>() as DWORD;
-    if minimized {
+    if headless {
+        si.dwFlags |= STARTF_USESHOWWINDOW;
+        si.wShowWindow = SW_HIDE;
+    } else if minimized {
         si.dwFlags |= STARTF_USESHOWWINDOW;
         si.wShowWindow = SW_SHOWMINIMIZED;
     }
@@ -175,7 +181,7 @@ unsafe fn launch(
         ptr::null_mut(),
         ptr::null_mut(),
         0, // bInheritHandles = FALSE
-        CREATE_SUSPENDED,
+        CREATE_SUSPENDED | if headless { CREATE_NO_WINDOW } else { 0 },
         ptr::null_mut(), // inherit environment
         wd_cstr.as_ptr().cast(),
         &si,

crates/openwa-test-runner/src/main.rs

@@ -15,6 +15,7 @@ use std::thread;
 use std::time::{Duration, Instant};
 
 const CREATE_NO_WINDOW: u32 = 0x0800_0000;
+const DETACHED_PROCESS: u32 = 0x0000_0008;
 
 // ─── Configuration ──────────────────────────────────────────────────────────
 

run-tests.ps1

@@ -5,4 +5,8 @@
 #   .\run-tests.ps1 longbow      # only tests matching "longbow"
 #   .\run-tests.ps1 -j 1         # serial mode
 
-cargo run -p openwa-test-runner --release -- @args
+# Build the test runner first to ensure it's up-to-date
+cargo build -p openwa-test-runner --release
+if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }
+
+& "$PSScriptRoot\target\i686-pc-windows-msvc\release\openwa-test.exe" @args