feat: improve pkgx binary detection

- Add user-specific installation path (~/.local/bin/pkgx)
- Use isExecutableFileAtPath for proper binary permission check

Sources/teaBASE+Helpers.m

@@ -69,8 +69,18 @@ - (BOOL)homebrewInstalled {
 }
 
 - (BOOL)pkgxInstalled {
-    //TODO need to check more locations
-    return [NSFileManager.defaultManager isReadableFileAtPath:@"/usr/local/bin/pkgx"];
+    NSArray *locations = @[
+        @"/usr/local/bin/pkgx", // system-wide
+        [NSString stringWithFormat:@"%@/.local/bin/pkgx", NSHomeDirectory()] // user-specific
+    ];
+
+    NSFileManager *fm = NSFileManager.defaultManager;
+    for (NSString *path in locations) {
+        if ([fm isExecutableFileAtPath:path]) {
+            return YES;
+        }
+    }
+    return NO;
 }
 
 @end