Add optional global gtag() exposure setting

New checkbox in General settings to conditionally expose window.gtag()
for compatibility with third-party scripts (e.g. HFCM). Defaults to
off, keeping only window.attCCGtag() available.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

admin/views/settings-general.php

@@ -101,6 +101,22 @@ if ( ! defined( 'ABSPATH' ) ) {
 			</td>
 		</tr>
 
+		<tr>
+			<th scope="row">
+				<?php esc_html_e( 'Global gtag Function', 'att-consent' ); ?>
+			</th>
+			<td>
+				<label for="expose_gtag_global">
+					<input type="checkbox" name="expose_gtag_global" id="expose_gtag_global" value="1"
+						   <?php checked( $settings['expose_gtag_global'] ); ?>>
+					<?php esc_html_e( 'Expose window.gtag() globally', 'att-consent' ); ?>
+				</label>
+				<p class="description">
+					<?php esc_html_e( 'Enable this if other plugins or custom scripts on your site call gtag() directly (e.g. HFCM snippets). When disabled, only window.attCCGtag() is available.', 'att-consent' ); ?>
+				</p>
+			</td>
+		</tr>
+
 		<tr>
 			<th scope="row">
 				<label for="floating_widget"><?php esc_html_e( 'Floating Widget', 'att-consent' ); ?></label>