feat(admin): Settings 分區即時儲存（backport A v3.0.2）

7 個設定分區各自加「儲存此區塊」按鈕，經 wp_ajax_wpdo_save_settings_section
以 AJAX 存檔，不再需要整頁 reload。

- 新增 ajax_save_settings_section() + 7 個 private save_section_*()
- 新增 admin/assets/wpdo-settings.js（106 行）與 4 條 CSS 規則
- render_settings() 的 7 個 h3 各包上 .wpdo-settings-section[data-section]
- 全頁送出按鈕改標「儲存全部設定」，原本的 POST handler 保持不變（漸進增強）

hp-transient / wc-term-count 兩個分區的 toggle 仍由核心 admin 呈現（實作在
AddOn），只寫 wp_options，故不需 class_exists 守衛。

admin/assets/wpdo-admin.css

@@ -513,3 +513,31 @@
 		animation: none;
 	}
 }
+
+/* ── Settings per-section instant save (v3.0.2 backport) ────────────── */
+
+.wpdo-settings-section {
+	background: var(--color-surface-card, #fbf7f0);
+	border: 1px solid var(--color-border-soft, #e5dccd);
+	border-radius: var(--radius-md, 12px);
+	padding: var(--space-4, 16px) var(--space-6, 24px);
+	margin-bottom: var(--space-5, 20px);
+}
+
+.wpdo-section-save-row {
+	display: flex;
+	align-items: center;
+	gap: var(--space-3, 12px);
+	padding-top: var(--space-3, 12px);
+}
+
+.wpdo-section-save-status {
+	font-size: 0.9rem;
+	color: var(--color-success, #5a8c5a);
+	opacity: 0;
+	transition: opacity var(--duration-normal, 200ms) var(--ease-default, ease);
+}
+
+.wpdo-section-save-status.visible {
+	opacity: 1;
+}

admin/assets/wpdo-settings.js

@@ -0,0 +1,106 @@
+/**
+ * WP Data Optimizer — Settings per-section instant save.
+ *
+ * Each .wpdo-settings-section card has a "儲存此區塊" button that posts only
+ * that section's fields via AJAX, updating options without a full page reload.
+ *
+ * @since 3.0.2
+ */
+/* global wpdoSettings */
+( function () {
+	'use strict';
+
+	if ( typeof wpdoSettings === 'undefined' ) {
+		return;
+	}
+
+	const { ajaxUrl, nonce, i18n } = wpdoSettings;
+
+	/**
+	 * Collect form fields within a section into a FormData object.
+	 * Unchecked checkboxes are intentionally omitted (server does isset() ? '1' : '0').
+	 *
+	 * @param {HTMLElement} section
+	 * @returns {FormData}
+	 */
+	function collectFields( section ) {
+		const fd = new FormData();
+		section.querySelectorAll( 'input, select, textarea' ).forEach( ( el ) => {
+			if ( ! el.name ) {
+				return;
+			}
+			if ( el.type === 'checkbox' ) {
+				if ( el.checked ) {
+					fd.append( el.name, el.value );
+				}
+			} else if ( el.type === 'radio' ) {
+				if ( el.checked ) {
+					fd.append( el.name, el.value );
+				}
+			} else {
+				fd.append( el.name, el.value );
+			}
+		} );
+		return fd;
+	}
+
+	/**
+	 * Show a transient status message, then fade it out after 2.5s.
+	 *
+	 * @param {HTMLElement} statusEl
+	 * @param {string}      message
+	 * @param {boolean}     isError
+	 */
+	function showStatus( statusEl, message, isError ) {
+		statusEl.textContent = message;
+		statusEl.style.color = isError ? 'var(--color-error, #b03d3d)' : 'var(--color-success, #5a8c5a)';
+		statusEl.classList.add( 'visible' );
+		clearTimeout( statusEl._wpdo_timer );
+		statusEl._wpdo_timer = setTimeout( () => {
+			statusEl.classList.remove( 'visible' );
+		}, 2500 );
+	}
+
+	document.addEventListener( 'click', function ( e ) {
+		const btn = e.target.closest( '.wpdo-section-save' );
+		if ( ! btn ) {
+			return;
+		}
+		const section    = btn.closest( '.wpdo-settings-section' );
+		const statusEl   = btn.nextElementSibling;
+		const sectionKey = section ? section.dataset.section : '';
+		if ( ! sectionKey ) {
+			return;
+		}
+
+		const originalLabel = btn.textContent;
+		btn.disabled        = true;
+		btn.textContent     = i18n.saving;
+
+		const fd = collectFields( section );
+		fd.append( 'action', 'wpdo_save_settings_section' );
+		fd.append( '_ajax_nonce', nonce );
+		fd.append( 'section', sectionKey );
+
+		fetch( ajaxUrl, {
+			method      : 'POST',
+			credentials : 'same-origin',
+			body        : fd,
+		} )
+			.then( ( r ) => r.json() )
+			.then( ( data ) => {
+				if ( data.success ) {
+					showStatus( statusEl, i18n.saved, false );
+				} else {
+					showStatus( statusEl, i18n.error, true );
+				}
+			} )
+			.catch( () => {
+				showStatus( statusEl, i18n.error, true );
+			} )
+			.finally( () => {
+				btn.disabled    = false;
+				btn.textContent = originalLabel;
+			} );
+	} );
+} )();

admin/class-tmdo-admin.php

@@ -44,6 +44,7 @@ class TMDO_Admin {
 		add_action( 'admin_enqueue_scripts', array( __CLASS__, 'enqueue_assets' ) );
 		add_action( 'network_admin_enqueue_scripts', array( __CLASS__, 'enqueue_assets' ) );
 		add_action( 'wp_ajax_wpdo_admin_action', array( __CLASS__, 'handle_ajax' ) );
+		add_action( 'wp_ajax_wpdo_save_settings_section', array( __CLASS__, 'ajax_save_settings_section' ) );
 		add_action( 'admin_notices', array( __CLASS__, 'maybe_nginx_backup_notice' ) );
 	}
 
@@ -300,6 +301,28 @@ class TMDO_Admin {
 				),
 			)
 		);
+
+		// Settings per-section instant save.
+		wp_enqueue_script(
+			'wpdo-settings',
+			TMDO_URL . 'admin/assets/wpdo-settings.js',
+			array(),
+			TMDO_VERSION,
+			true
+		);
+		wp_localize_script(
+			'wpdo-settings',
+			'wpdoSettings',
+			array(
+				'ajaxUrl' => admin_url( 'admin-ajax.php' ),
+				'nonce'   => wp_create_nonce( 'wpdo_save_settings' ),
+				'i18n'    => array(
+					'saving' => __( '儲存中…', '2meet-data-optimizer' ),
+					'saved'  => __( '✓ 已儲存', '2meet-data-optimizer' ),
+					'error'  => __( '儲存失敗，請重試。', '2meet-data-optimizer' ),
+				),
+			)
+		);
 	}
 
 	/**
@@ -3211,6 +3234,7 @@ wpdo.getListings({ per_page: 3 }).then(r => console.log(r));'
 			<?php wp_nonce_field( 'wpdo_save_settings' ); ?>
 			<input type="hidden" name="wpdo_save_settings" value="1">
 
+			<div class="wpdo-settings-section" data-section="notifications">
 			<h3><?php esc_html_e( '📧 Email 警報', '2meet-data-optimizer' ); ?></h3>
 			<p class="description"><?php esc_html_e( '預設關閉。啟用後，每日健康檢查 cron 發現 critical 警告時會發信。同一個警告在 throttle 視窗內不重發。', '2meet-data-optimizer' ); ?></p>
 			<table class="form-table" role="presentation">
@@ -3311,6 +3335,12 @@ wpdo.getListings({ per_page: 3 }).then(r => console.log(r));'
 			}
 			?>
 
+			<div class="wpdo-section-save-row">
+				<button type="button" class="button wpdo-section-save"><?php esc_html_e( '儲存此區塊', '2meet-data-optimizer' ); ?></button>
+				<span class="wpdo-section-save-status" aria-live="polite"></span>
+			</div>
+			</div><!-- /.wpdo-settings-section -->
+			<div class="wpdo-settings-section" data-section="entity-bridge">
 			<h3 style="margin-top: 2em;"><?php esc_html_e( '⚡ Entity Bridge（v2.5.4 / post v2.11.0）', '2meet-data-optimizer' ); ?></h3>
 			<p class="description">
 				<?php esc_html_e( 'Hook Bus 攔截 WordPress 原生 metadata filter，將 user / post / term / comment meta 路由至扁平化資料表。', '2meet-data-optimizer' ); ?><br>
@@ -3387,6 +3417,12 @@ wpdo.getListings({ per_page: 3 }).then(r => console.log(r));'
 				    OR option_name LIKE '\\_transient\\_timeout\\_wpdo\\_hp\\_pm\\_%'"
 			);
 			?>
+			<div class="wpdo-section-save-row">
+				<button type="button" class="button wpdo-section-save"><?php esc_html_e( '儲存此區塊', '2meet-data-optimizer' ); ?></button>
+				<span class="wpdo-section-save-status" aria-live="polite"></span>
+			</div>
+			</div><!-- /.wpdo-settings-section -->
+			<div class="wpdo-settings-section" data-section="hp-transient">
 			<h3 style="margin-top: 2em;"><?php esc_html_e( '🌿 HivePress Transient Filter（v2.11.5）', '2meet-data-optimizer' ); ?></h3>
 			<p class="description">
 				<?php esc_html_e( 'HivePress 內部用 update_post_meta($post_id, \'_transient_<name>\', $value) 把 TTL cache 寫進 wp_postmeta（每個 hp_listing publish 觸發 8-16 個 transient row）。本 filter 在 metadata 層攔截並重新路由到 wp_options（native transient API），HivePress 完全無感，wp_postmeta 保持乾淨。Filter 是 metadata 層運作，不依賴 mode promote。', '2meet-data-optimizer' ); ?>
@@ -3477,6 +3513,12 @@ wpdo.getListings({ per_page: 3 }).then(r => console.log(r));'
 				    OR meta_key IN ('_hp_price','_hp_status','_hp_featured','_hp_verified','_hp_view_count','_thumbnail_id','_edit_lock','_edit_last')"
 			);
 			?>
+			<div class="wpdo-section-save-row">
+				<button type="button" class="button wpdo-section-save"><?php esc_html_e( '儲存此區塊', '2meet-data-optimizer' ); ?></button>
+				<span class="wpdo-section-save-status" aria-live="polite"></span>
+			</div>
+			</div><!-- /.wpdo-settings-section -->
+			<div class="wpdo-settings-section" data-section="garbage-filter">
 			<h3 style="margin-top: 2em;"><?php esc_html_e( '🗑 Term + Comment Garbage Filter（v2.12.1）', '2meet-data-optimizer' ); ?></h3>
 			<p class="description">
 				<?php esc_html_e( '攔截 wp_termmeta / wp_commentmeta 已知垃圾 keys 的寫入並 silent drop（_wxr_import_* WP 匯入殘留、_2meet_demo_* demo 標記、commentmeta 中 8 個誤寫的 post-domain orphan keys）。Phase 0 cleanup CLI 清歷史，本 filter 防再次累積。Read 路徑不攔截（向後相容）。', '2meet-data-optimizer' ); ?>
@@ -3557,6 +3599,12 @@ wpdo.getListings({ per_page: 3 }).then(r => console.log(r));'
 				 WHERE option_name LIKE '\\_transient\\_wpdo\\_wc\\_termcount\\_%'"
 			);
 			?>
+			<div class="wpdo-section-save-row">
+				<button type="button" class="button wpdo-section-save"><?php esc_html_e( '儲存此區塊', '2meet-data-optimizer' ); ?></button>
+				<span class="wpdo-section-save-status" aria-live="polite"></span>
+			</div>
+			</div><!-- /.wpdo-settings-section -->
+			<div class="wpdo-settings-section" data-section="wc-term-count">
 			<h3 style="margin-top: 2em;"><?php esc_html_e( '🛒 WooCommerce Term Count Filter（v2.12.3）', '2meet-data-optimizer' ); ?></h3>
 			<p class="description">
 				<?php esc_html_e( '攔截 WooCommerce 寫入 wp_termmeta 的 product_count_<taxonomy> cache rows，重新路由到 wp_options（native transient 結構）。WC 自身 cache 失效邏輯不變（每次新增/刪除 product 時會重算寫入），僅儲存位置改變。Read 路徑亦會優先從 wp_options 讀回，cache miss 才 fall-through 至 wp_termmeta（向後相容）。', '2meet-data-optimizer' ); ?>
@@ -3619,6 +3667,12 @@ wpdo.getListings({ per_page: 3 }).then(r => console.log(r));'
 				? TMDO_Term_Comment_Misc_Bucket::count_rows( 'comment' )
 				: 0;
 			?>
+			<div class="wpdo-section-save-row">
+				<button type="button" class="button wpdo-section-save"><?php esc_html_e( '儲存此區塊', '2meet-data-optimizer' ); ?></button>
+				<span class="wpdo-section-save-status" aria-live="polite"></span>
+			</div>
+			</div><!-- /.wpdo-settings-section -->
+			<div class="wpdo-settings-section" data-section="misc-bucket">
 			<h3 style="margin-top: 2em;"><?php esc_html_e( '📦 Term + Comment Misc Bucket（v2.12.4）', '2meet-data-optimizer' ); ?></h3>
 			<p class="description">
 				<?php esc_html_e( 'Catch-all flat 表，捕捉所有未被前面 filter 處理的 term/comment meta keys（priority 99，整條 filter chain 的最後一棒）。讓 wp_termmeta / wp_commentmeta 完全可避開（v3.0.0 DROP 前置條件）。寫入 wp_wpdo_term_misc / wp_wpdo_comment_misc 兩張 K/V 表，PRIMARY KEY (entity_id, meta_key)。讀取 cache miss 時 fall-through 至 wp_*meta 維持向後相容。', '2meet-data-optimizer' ); ?>
@@ -3665,6 +3719,12 @@ wpdo.getListings({ per_page: 3 }).then(r => console.log(r));'
 				</tbody>
 			</table>
 
+			<div class="wpdo-section-save-row">
+				<button type="button" class="button wpdo-section-save"><?php esc_html_e( '儲存此區塊', '2meet-data-optimizer' ); ?></button>
+				<span class="wpdo-section-save-status" aria-live="polite"></span>
+			</div>
+			</div><!-- /.wpdo-settings-section -->
+			<div class="wpdo-settings-section" data-section="automator">
 			<h3 style="margin-top: 2em;"><?php esc_html_e( '🤖 FSM Automator（v2.5.0 M13）', '2meet-data-optimizer' ); ?></h3>
 			<p class="description"><?php esc_html_e( '預設關閉。啟用後，每日 04:30 UTC 跑一次，自動執行 FSM Advisor 標記為 PROMOTE 的 module 推進。Destructive 轉態（verify→cutover、cutover→cleanup、cleanup→complete）即使 enabled 也永不自動。', '2meet-data-optimizer' ); ?></p>
 			<table class="form-table" role="presentation">
@@ -3703,10 +3763,134 @@ wpdo.getListings({ per_page: 3 }).then(r => console.log(r));'
 				</tbody>
 			</table>
 
-			<?php submit_button( __( '儲存設定', '2meet-data-optimizer' ) ); ?>
+			<div class="wpdo-section-save-row">
+				<button type="button" class="button wpdo-section-save"><?php esc_html_e( '儲存此區塊', '2meet-data-optimizer' ); ?></button>
+				<span class="wpdo-section-save-status" aria-live="polite"></span>
+			</div>
+			</div><!-- /.wpdo-settings-section -->
+			<?php submit_button( __( '儲存全部設定', '2meet-data-optimizer' ) ); ?>
 		</form>
 		<?php
 	}
+
+	// ── Per-section save helpers ──────────────────────────────────────────
+	// These private helpers are always invoked from ajax_save_settings_section()
+	// which calls check_ajax_referer() first. PHPCS cannot trace the call chain.
+	// phpcs:disable WordPress.Security.NonceVerification.Missing -- nonce checked by ajax_save_settings_section() caller
+	// phpcs:disable Squiz.Commenting.FunctionComment.Missing,Squiz.Commenting.FunctionComment.WrongStyle -- internal helpers
+
+	private static function save_section_notifications(): void {
+		update_option( 'wpdo_email_alerts_enabled', isset( $_POST['wpdo_email_alerts_enabled'] ) ? '1' : '0', false );
+		$recipient = isset( $_POST['wpdo_alert_email'] ) ? sanitize_email( wp_unslash( (string) $_POST['wpdo_alert_email'] ) ) : '';
+		update_option( 'wpdo_alert_email', $recipient, false );
+		$throttle = isset( $_POST['wpdo_alert_throttle_hours'] ) ? max( 1, min( 168, (int) $_POST['wpdo_alert_throttle_hours'] ) ) : 24;
+		update_option( 'wpdo_alert_throttle_hours', $throttle, false );
+		foreach ( array( 'slack', 'discord', 'telegram' ) as $ch ) {
+			update_option( "wpdo_{$ch}_enabled", isset( $_POST[ "wpdo_{$ch}_enabled" ] ) ? '1' : '0', false );
+			$thr = isset( $_POST[ "wpdo_{$ch}_throttle_hours" ] ) ? max( 1, min( 168, (int) $_POST[ "wpdo_{$ch}_throttle_hours" ] ) ) : 24;
+			update_option( "wpdo_{$ch}_throttle_hours", $thr, false );
+			$sev = isset( $_POST[ "wpdo_{$ch}_severity" ] ) ? sanitize_key( wp_unslash( (string) $_POST[ "wpdo_{$ch}_severity" ] ) ) : 'critical_only';
+			if ( ! in_array( $sev, array( 'critical_only', 'critical_and_recommended' ), true ) ) {
+				$sev = 'critical_only';
+			}
+			update_option( "wpdo_{$ch}_severity", $sev, false );
+		}
+		foreach ( array( 'wpdo_slack_webhook', 'wpdo_discord_webhook' ) as $webhook_key ) {
+			if ( ! isset( $_POST[ $webhook_key ] ) ) {
+				continue;
+			}
+			$webhook = esc_url_raw( wp_unslash( (string) $_POST[ $webhook_key ] ) );
+			if ( '' === $webhook ) {
+				continue;
+			}
+			if ( class_exists( 'TMDO_Crypto' ) ) {
+				TMDO_Crypto::set_option( $webhook_key, $webhook );
+			} else {
+				update_option( $webhook_key, $webhook, false );
+			}
+		}
+		if ( isset( $_POST['wpdo_telegram_bot_token'] ) ) {
+			$token = sanitize_text_field( wp_unslash( (string) $_POST['wpdo_telegram_bot_token'] ) );
+			if ( '' !== $token ) {
+				if ( class_exists( 'TMDO_Crypto' ) ) {
+					TMDO_Crypto::set_option( 'wpdo_telegram_bot_token', $token );
+				} else {
+					update_option( 'wpdo_telegram_bot_token', $token, false );
+				}
+			}
+		}
+		if ( isset( $_POST['wpdo_telegram_chat_id'] ) ) {
+			update_option( 'wpdo_telegram_chat_id', sanitize_text_field( wp_unslash( (string) $_POST['wpdo_telegram_chat_id'] ) ), false );
+		}
+	}
+
+	private static function save_section_entity_bridge(): void {
+		update_option( 'wpdo_hook_bus_enabled', isset( $_POST['wpdo_hook_bus_enabled'] ) ? '1' : '0', false );
+		if ( class_exists( 'TMDO_Mode_Manager' ) ) {
+			foreach ( array( 'user', 'post', 'term', 'comment' ) as $entity_type ) {
+				$new_mode = isset( $_POST[ 'wpdo_bridge_mode_' . $entity_type ] )
+					? sanitize_key( wp_unslash( (string) $_POST[ 'wpdo_bridge_mode_' . $entity_type ] ) )
+					: '';
+				if ( TMDO_Mode_Manager::is_valid_mode( $new_mode ) ) {
+					TMDO_Mode_Manager::set( $entity_type, $new_mode );
+				}
+			}
+			TMDO_Mode_Manager::reset_cache();
+		}
+		if ( class_exists( 'TMDO_Hook_Bus_Bridge' ) ) {
+			TMDO_Hook_Bus_Bridge::reset_cache();
+		}
+	}
+
+	private static function save_section_hp_transient(): void {
+		update_option( 'wpdo_hp_transient_filter_enabled', isset( $_POST['wpdo_hp_transient_filter_enabled'] ) ? '1' : '0', false );
+	}
+
+	private static function save_section_garbage_filter(): void {
+		update_option( 'wpdo_term_comment_garbage_filter_enabled', isset( $_POST['wpdo_term_comment_garbage_filter_enabled'] ) ? '1' : '0', false );
+	}
+
+	private static function save_section_wc_term_count(): void {
+		update_option( 'wpdo_wc_term_count_filter_enabled', isset( $_POST['wpdo_wc_term_count_filter_enabled'] ) ? '1' : '0', false );
+	}
+
+	private static function save_section_misc_bucket(): void {
+		update_option( 'wpdo_term_comment_misc_bucket_enabled', isset( $_POST['wpdo_term_comment_misc_bucket_enabled'] ) ? '1' : '0', false );
+	}
+
+	private static function save_section_automator(): void {
+		update_option( 'wpdo_automator_enabled', isset( $_POST['wpdo_automator_enabled'] ) ? '1' : '0', false );
+		$blacklist = isset( $_POST['wpdo_automator_blacklist'] ) && is_array( $_POST['wpdo_automator_blacklist'] )
+			? array_values( array_filter( array_map( 'sanitize_key', wp_unslash( $_POST['wpdo_automator_blacklist'] ) ) ) )
+			: array();
+		update_option( 'wpdo_automator_blacklist', $blacklist, false );
+	}
+	// phpcs:enable WordPress.Security.NonceVerification.Missing,Squiz.Commenting.FunctionComment.Missing,Squiz.Commenting.FunctionComment.WrongStyle
+
+	/**
+	 * AJAX: save a single settings section without a full page reload.
+	 */
+	public static function ajax_save_settings_section(): void {
+		check_ajax_referer( 'wpdo_save_settings' );
+		if ( ! TMDO_Capability::current_user_can_admin() ) {
+			wp_send_json_error( 'unauthorized', 403 );
+		}
+		$section  = isset( $_POST['section'] ) ? sanitize_key( wp_unslash( (string) $_POST['section'] ) ) : '';
+		$handlers = array(
+			'notifications'  => 'save_section_notifications',
+			'entity-bridge'  => 'save_section_entity_bridge',
+			'hp-transient'   => 'save_section_hp_transient',
+			'garbage-filter' => 'save_section_garbage_filter',
+			'wc-term-count'  => 'save_section_wc_term_count',
+			'misc-bucket'    => 'save_section_misc_bucket',
+			'automator'      => 'save_section_automator',
+		);
+		if ( ! isset( $handlers[ $section ] ) ) {
+			wp_send_json_error( 'invalid_section', 400 );
+		}
+		self::{$handlers[ $section ]}();
+		wp_send_json_success( array( 'message' => __( '設定已儲存。', '2meet-data-optimizer' ) ) );
+	}
 }
 
 // Boot admin hooks.