upgrade: adopt V8.21.3 (V8.13→8.21.3: P5 SFTP/S3, P6 multilingual, editor overhaul, enterprise hardening)

Overlay ~150 upstream items onto our V8.12 base, preserving trade-pro
theme, registry tests, and design docs. Re-applied our patch set
(discovery/env_for/blocks.css/type-mapping/theme_color/frontend entries,
test_theme_pro_v3 mods) — all anchors survived upstream evolution.

New platform enhancement (fixes upgrade-introduced regression):
multilingual.site_locale now honors settings_json.locale, plus
PUT /api/i18n/sites/{id}/locale — standalone English sites get
<html lang='en'> under the V8.15 locale-rewrite pipeline.

compose: adopt V8.21.3 (image 8.21.3-dev.1, /api/ready probes, MySQL/S3
env) with project name pinned to siteforge-v8-10 (data volumes).

Tests: 356 passed / 11 failed — all 11 confirmed pre-existing in
pristine V8.21.3 on this host (10 upstream Windows env + our build test
now green after locale fix). Patch registry updated in plan doc.

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

themes/automotive/pro.html

@@ -7,4 +7,7 @@
 {% if has_custom and kind!='notfound' %}<main id="main-content" class="sf-canvas pro-custom-content">{{custom_blocks}}</main>{% else %}<main id="main-content" class="sf-canvas pro-custom-content" aria-hidden="true"></main>{% endif %}
 {% if kind not in ('notfound','search') %}<section class="pro-end-cta"><div class="pro-wrap"><div><span class="pro-eyebrow">LET'S CONNECT</span><h2>从这里开始下一步。</h2><p>{{site.tagline or '了解更多产品、服务与合作信息。'}}</p></div><a href="/contact/">联系我们 <span>↗</span></a></div></section>{% endif %}
 <footer class="sf-site-foot pro-footer"><div class="pro-wrap"><div class="pro-footer-top"><div><span class="pro-eyebrow">DRIVEN BY PURPOSE</span><h2>{{chrome.footer.title or site.name}}</h2><p>{{footer_text}}</p></div><div class="pro-footer-links">{{footer_links(footer_nav)}}</div><div><span class="pro-eyebrow">LET'S TALK</span><p>{{footer_email or '请在后台配置企业联系方式'}}</p></div></div><div class="pro-footer-bottom"><span>© {{year}} {{site.name}}</span><span>SITEFORGE / STATIC SITE</span></div></div></footer>
+
+{% if chrome.mobile_tabs['enabled'] and chrome.mobile_tabs['items'] %}<nav class="sf-mobile-tabs" style="--sf-mobile-tab-count:{{ chrome.mobile_tabs['items']|length }}" aria-label="手机底部快捷导航" data-mobile-tabs>
+{% for tab in chrome.mobile_tabs['items'] %}{% if tab.action == 'menu' %}<button type="button" class="sf-mobile-tab" data-mobile-open-menu aria-label="{{tab.title}}"><span class="sf-tab-icon" aria-hidden="true">{{ mobile_tab_icons[tab.icon] }}</span><span class="sf-tab-label">{{tab.title}}</span></button>{% else %}<a class="sf-mobile-tab" href="{{tab.route}}"{% if tab.route == route %} aria-current="page"{% endif %}><span class="sf-tab-icon" aria-hidden="true">{{ mobile_tab_icons[tab.icon] }}</span><span class="sf-tab-label">{{tab.title}}</span></a>{% endif %}{% endfor %}</nav>{% endif %}
 <script defer src="assets/site-runtime.js"></script><script defer src="assets/pro.js"></script></body></html>

themes/corporate/pro.html

@@ -7,4 +7,7 @@
 {% if has_custom and kind!='notfound' %}<main id="main-content" class="sf-canvas pro-custom-content">{{custom_blocks}}</main>{% else %}<main id="main-content" class="sf-canvas pro-custom-content" aria-hidden="true"></main>{% endif %}
 {% if kind not in ('notfound','search') %}<section class="pro-end-cta"><div class="pro-wrap"><div><span class="pro-eyebrow">LET'S CONNECT</span><h2>从这里开始下一步。</h2><p>{{site.tagline or '了解更多产品、服务与合作信息。'}}</p></div><a href="/contact/">联系我们 <span>↗</span></a></div></section>{% endif %}
 <footer class="sf-site-foot pro-footer"><div class="pro-wrap"><div class="pro-footer-top"><div><span class="pro-eyebrow">A BETTER WAY FORWARD</span><h2>{{chrome.footer.title or site.name}}</h2><p>{{footer_text}}</p></div><div class="pro-footer-links">{{footer_links(footer_nav)}}</div><div><span class="pro-eyebrow">CONTACT OUR TEAM</span><p>{{footer_email or '请在后台配置企业联系方式'}}</p></div></div><div class="pro-footer-bottom"><span>© {{year}} {{site.name}}</span><span>BUILDING LONG-TERM VALUE</span></div></div></footer>
+
+{% if chrome.mobile_tabs['enabled'] and chrome.mobile_tabs['items'] %}<nav class="sf-mobile-tabs" style="--sf-mobile-tab-count:{{ chrome.mobile_tabs['items']|length }}" aria-label="手机底部快捷导航" data-mobile-tabs>
+{% for tab in chrome.mobile_tabs['items'] %}{% if tab.action == 'menu' %}<button type="button" class="sf-mobile-tab" data-mobile-open-menu aria-label="{{tab.title}}"><span class="sf-tab-icon" aria-hidden="true">{{ mobile_tab_icons[tab.icon] }}</span><span class="sf-tab-label">{{tab.title}}</span></button>{% else %}<a class="sf-mobile-tab" href="{{tab.route}}"{% if tab.route == route %} aria-current="page"{% endif %}><span class="sf-tab-icon" aria-hidden="true">{{ mobile_tab_icons[tab.icon] }}</span><span class="sf-tab-label">{{tab.title}}</span></a>{% endif %}{% endfor %}</nav>{% endif %}
 <script defer src="assets/site-runtime.js"></script><script defer src="assets/pro.js"></script></body></html>

themes/industrial/pro.html

@@ -7,4 +7,7 @@
 {% if has_custom and kind!='notfound' %}<main id="main-content" class="sf-canvas pro-custom-content">{{custom_blocks}}</main>{% else %}<main id="main-content" class="sf-canvas pro-custom-content" aria-hidden="true"></main>{% endif %}
 {% if kind not in ('notfound','search') %}<section class="pro-end-cta"><div class="pro-wrap"><div><span class="pro-eyebrow">LET'S CONNECT</span><h2>从这里开始下一步。</h2><p>{{site.tagline or '了解更多产品、服务与合作信息。'}}</p></div><a href="/contact/">联系我们 <span>↗</span></a></div></section>{% endif %}
 <footer class="sf-site-foot pro-footer"><div class="pro-wrap"><div class="pro-footer-top"><div><span class="pro-eyebrow">INDUSTRIAL PARTNERSHIP</span><h2>{{chrome.footer.title or site.name}}</h2><p>{{footer_text}}</p></div><div class="pro-footer-links">{{footer_links(footer_nav)}}</div><div><span class="pro-eyebrow">BUSINESS ENQUIRY</span><p>{{footer_email or '请在后台配置企业联系方式'}}</p></div></div><div class="pro-footer-bottom"><span>© {{year}} {{site.name}}</span><span>ENGINEERED TO DELIVER</span></div></div></footer>
+
+{% if chrome.mobile_tabs['enabled'] and chrome.mobile_tabs['items'] %}<nav class="sf-mobile-tabs" style="--sf-mobile-tab-count:{{ chrome.mobile_tabs['items']|length }}" aria-label="手机底部快捷导航" data-mobile-tabs>
+{% for tab in chrome.mobile_tabs['items'] %}{% if tab.action == 'menu' %}<button type="button" class="sf-mobile-tab" data-mobile-open-menu aria-label="{{tab.title}}"><span class="sf-tab-icon" aria-hidden="true">{{ mobile_tab_icons[tab.icon] }}</span><span class="sf-tab-label">{{tab.title}}</span></button>{% else %}<a class="sf-mobile-tab" href="{{tab.route}}"{% if tab.route == route %} aria-current="page"{% endif %}><span class="sf-tab-icon" aria-hidden="true">{{ mobile_tab_icons[tab.icon] }}</span><span class="sf-tab-label">{{tab.title}}</span></a>{% endif %}{% endfor %}</nav>{% endif %}
 <script defer src="assets/site-runtime.js"></script><script defer src="assets/pro.js"></script></body></html>

themes/minimal/pro.html

@@ -7,4 +7,7 @@
 {% if has_custom and kind!='notfound' %}<main id="main-content" class="sf-canvas pro-custom-content">{{custom_blocks}}</main>{% else %}<main id="main-content" class="sf-canvas pro-custom-content" aria-hidden="true"></main>{% endif %}
 {% if kind not in ('notfound','search') %}<section class="pro-end-cta"><div class="pro-wrap"><div><span class="pro-eyebrow">LET'S CONNECT</span><h2>从这里开始下一步。</h2><p>{{site.tagline or '了解更多产品、服务与合作信息。'}}</p></div><a href="/contact/">联系我们 <span>↗</span></a></div></section>{% endif %}
 <footer class="sf-site-foot pro-footer"><div class="pro-wrap"><div class="pro-footer-top"><div><span class="pro-eyebrow">STAY CURIOUS</span><h2>{{chrome.footer.title or site.name}}<span class="pro-dot">.</span></h2><p>{{footer_text}}</p></div><div class="pro-footer-links">{{footer_links(footer_nav)}}</div><div><span class="pro-eyebrow">SAY HELLO</span><p>{{footer_email or '请在后台配置企业联系方式'}}</p></div></div><div class="pro-footer-bottom"><span>© {{year}} {{site.name}}</span><span>MADE WITH INTENTION</span></div></div></footer>
+
+{% if chrome.mobile_tabs['enabled'] and chrome.mobile_tabs['items'] %}<nav class="sf-mobile-tabs" style="--sf-mobile-tab-count:{{ chrome.mobile_tabs['items']|length }}" aria-label="手机底部快捷导航" data-mobile-tabs>
+{% for tab in chrome.mobile_tabs['items'] %}{% if tab.action == 'menu' %}<button type="button" class="sf-mobile-tab" data-mobile-open-menu aria-label="{{tab.title}}"><span class="sf-tab-icon" aria-hidden="true">{{ mobile_tab_icons[tab.icon] }}</span><span class="sf-tab-label">{{tab.title}}</span></button>{% else %}<a class="sf-mobile-tab" href="{{tab.route}}"{% if tab.route == route %} aria-current="page"{% endif %}><span class="sf-tab-icon" aria-hidden="true">{{ mobile_tab_icons[tab.icon] }}</span><span class="sf-tab-label">{{tab.title}}</span></a>{% endif %}{% endfor %}</nav>{% endif %}
 <script defer src="assets/site-runtime.js"></script><script defer src="assets/pro.js"></script></body></html>