feat: fetch add wait_until parameter for page loads options

Add `--wait_until` and `--wait_ms` CLI arguments to configure session wait behavior. Updates `Session.wait` to evaluate specific page load states (`load`, `domcontentloaded`, `networkidle`, `fixed`) before completing the wait loop.

src/cdp/testing.zig

@@ -136,7 +136,7 @@ const TestContext = struct {
                 0,
             );
             try page.navigate(full_url, .{});
-            _ = bc.session.wait(2000);
+            _ = bc.session.wait(2000, .load);
         }
         return bc;
     }