fix(browse): windowsHide sweep — flag every residual child_process site + full-census tripwire (#2160, #2415)

Add windowsHide:true at every remaining direct child_process call in
browse/src that could flash a console window on Windows:

- project-slug.ts (execSync gstack-slug)
- browser-skills.ts (cp.spawnSync git rev-parse)
- security-sidecar-client.ts (spawn — the LONG-LIVED Node sidecar, whose
  missing flag parked a console window on the taskbar for the daemon's
  whole lifetime)
- find-security-sidecar.ts (execFileSync node --version)
- meta-commands.ts (execSync git rev-parse in inbox + the osascript
  activate call)
- browse-client.ts (cp.spawnSync git rev-parse)
- file-permissions.ts (execFileSync whoami.exe — Windows-only, ran bare)
- cli.ts (nodeSpawn osascript)

windows-spawn-hide.test.ts gains a SWEEP test on top of the existing
needles: it censuses EVERY child_process binding in src/ (static imports
incl. aliases, `await import()` / require destructures, and `import * as
cp` namespaces — 15 call sites across 10 files today) and fails CI on any
call without windowsHide within its options window. Exemptions carry
reasons — the one today is domain-skill-commands' interactive $EDITOR
spawn (stdio:'inherit'; CREATE_NO_WINDOW would detach a console editor
into an invisible console).

Tests: windows-spawn-hide 5 pass; file-permissions 19 pass; browse-client
28 pass; browser-skill-commands 29 pass (81/81 combined).

Fixes the app-side half of #2160; closes out #2415's residuals.

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

browse/src/browse-client.ts

@@ -103,7 +103,7 @@ export function resolveBrowseAuth(opts: BrowseClientOptions = {}): ResolvedAuth
 
 function defaultStateFile(): string | null {
   try {
-    const proc = cp.spawnSync('git', ['rev-parse', '--show-toplevel'], { encoding: 'utf-8', timeout: 2000 });
+    const proc = cp.spawnSync('git', ['rev-parse', '--show-toplevel'], { encoding: 'utf-8', timeout: 2000, windowsHide: true });
     const root = proc.status === 0 ? proc.stdout.trim() : null;
     const base = root || process.cwd();
     return path.join(base, '.gstack', 'browse.json');

browse/src/browser-skills.ts

@@ -98,7 +98,7 @@ export function defaultTierPaths(opts: { projectRoot?: string; home?: string; bu
 
 function detectProjectRoot(): string | null {
   try {
-    const proc = cp.spawnSync('git', ['rev-parse', '--show-toplevel'], { encoding: 'utf-8', timeout: 2000 });
+    const proc = cp.spawnSync('git', ['rev-parse', '--show-toplevel'], { encoding: 'utf-8', timeout: 2000, windowsHide: true });
     if (proc.status === 0) {
       const out = proc.stdout.trim();
       return out || null;

browse/src/cli.ts

@@ -310,6 +310,7 @@ function raiseHeadedWindowMacOS(): void {
     nodeSpawn('osascript', ['-e', 'tell application "Google Chrome for Testing" to activate'], {
       stdio: 'ignore',
       detached: true,
+      windowsHide: true,
     }).unref();
   } catch {
     // osascript missing or app not present — non-fatal

browse/src/file-permissions.ts

@@ -60,6 +60,7 @@ function currentUserSid(): string | null {
     const systemRoot = process.env.SystemRoot || process.env.windir || 'C:\\Windows';
     const out = execFileSync(`${systemRoot}\\System32\\whoami.exe`, ['/user', '/fo', 'csv', '/nh'], {
       encoding: 'utf8',
+      windowsHide: true,
     });
     const match = out.match(/S-1-[\d-]+/);
     cachedSid = match ? match[0] : null;

browse/src/find-security-sidecar.ts

@@ -30,7 +30,7 @@ export interface SidecarLocation {
 
 function nodeOnPath(): string | null {
   try {
-    execFileSync("node", ["--version"], { stdio: "ignore", timeout: 2000 });
+    execFileSync("node", ["--version"], { stdio: "ignore", timeout: 2000, windowsHide: true });
     return "node";
   } catch {
     return null;

browse/src/meta-commands.ts

@@ -777,7 +777,7 @@ export async function handleMetaCommand(
         let activated = false;
         for (const appName of appNames) {
           try {
-            execSync(`osascript -e 'tell application "${appName}" to activate'`, { stdio: 'pipe', timeout: 3000 });
+            execSync(`osascript -e 'tell application "${appName}" to activate'`, { stdio: 'pipe', timeout: 3000, windowsHide: true });
             activated = true;
             break;
           } catch (err: any) {
@@ -841,7 +841,7 @@ export async function handleMetaCommand(
       const { execSync } = await import('child_process');
       let gitRoot: string;
       try {
-        gitRoot = execSync('git rev-parse --show-toplevel', { encoding: 'utf-8', stdio: ['pipe', 'pipe', 'pipe'] }).trim();
+        gitRoot = execSync('git rev-parse --show-toplevel', { encoding: 'utf-8', stdio: ['pipe', 'pipe', 'pipe'], windowsHide: true }).trim();
       } catch (err: any) {
         // execSync throws with exit status on non-git directories
         if (err?.status === undefined && !err?.message?.includes('Command failed')) throw err;

browse/src/project-slug.ts

@@ -21,7 +21,7 @@ export function getCurrentProjectSlug(): string {
   }
   try {
     const slugBin = path.join(os.homedir(), '.claude/skills/gstack/bin/gstack-slug');
-    const out = execSync(slugBin, { encoding: 'utf8', timeout: 2000 }).trim();
+    const out = execSync(slugBin, { encoding: 'utf8', timeout: 2000, windowsHide: true }).trim();
     const m = out.match(/SLUG="?([^"\n]+)"?/);
     cachedSlug = m ? m[1]! : (out || 'unknown');
   } catch {

browse/src/security-sidecar-client.ts

@@ -138,6 +138,9 @@ function spawnSidecar(): boolean {
     const child = spawn(location.node, [location.entry], {
       stdio: ["pipe", "pipe", "pipe"],
       detached: false,
+      // Long-lived Node sidecar — without this, Windows gives it a console
+      // window that sits on the taskbar for the daemon's whole lifetime.
+      windowsHide: true,
     });
     child.stdout.on("data", (chunk: Buffer) => {
       s.buffer += chunk.toString("utf-8");