feat: add mobile update workspace navigation (Closes #967)

frontend/dashboard.css

@@ -469,26 +469,28 @@ textarea { resize: vertical; min-height: 120px; }
 .issue-sheet-panel { width:min(560px,100%); height:100%; overflow:auto; padding:18px; background:#0b1526; border-left:1px solid #2a496e; }
 .issue-sheet-header { display:flex; align-items:center; justify-content:space-between; gap:10px; }
 .issue-sheet-header button { min-height:44px; }
-.mobile-issue-detail-nav, .mobile-pull-detail-nav { display:none; }
+.mobile-issue-detail-nav, .mobile-pull-detail-nav, .mobile-update-detail-nav { display:none; }
 @media (max-width:600px) {
-  .issue-sheet-panel, .pull-sheet-panel { padding-top:max(12px,env(safe-area-inset-top)); }
-  .mobile-issue-detail-nav, .mobile-pull-detail-nav {
+  .issue-sheet-panel, .pull-sheet-panel, .update-sheet-panel { padding-top:max(12px,env(safe-area-inset-top)); }
+  .mobile-issue-detail-nav, .mobile-pull-detail-nav, .mobile-update-detail-nav {
     position:sticky; top:env(safe-area-inset-top); z-index:6;
     display:grid; grid-template-columns:repeat(4,minmax(0,1fr)); gap:4px;
     margin:8px -6px 12px; padding:6px;
     background:rgba(11,21,38,.98); border-block:1px solid #2a496e;
   }
-  .mobile-issue-detail-nav button, .mobile-pull-detail-nav button {
+  .mobile-issue-detail-nav button, .mobile-pull-detail-nav button, .mobile-update-detail-nav button {
     min-width:0; min-height:44px; padding:4px; overflow-wrap:anywhere;
     border-color:transparent; font-size:12px;
   }
-  .mobile-issue-detail-nav button[aria-current="location"], .mobile-pull-detail-nav button[aria-current="location"] {
+  .mobile-issue-detail-nav button[aria-current="location"], .mobile-pull-detail-nav button[aria-current="location"], .mobile-update-detail-nav button[aria-current="location"] {
     border-color:#60a5fa; background:#17365a; color:#fff;
   }
   #issue-overview, #issue-conversation, #issue-comment, #issue-planning { scroll-margin-top:72px; }
   #pull-overview, #pull-conversation, #pull-comment, #pull-review { scroll-margin-top:72px; }
+  #update-conversation, #update-subject-context, #update-reply-workspace { scroll-margin-top:72px; }
 }
 @media (min-width:601px) { .mobile-issue-detail-nav, .mobile-pull-detail-nav { display:none; } }
+@media (min-width:601px) { .mobile-update-detail-nav { display:none; } }
 .completed-filed-actions { position:fixed; right:0; bottom:0; z-index:57; box-sizing:border-box; width:min(560px,100%); display:grid; grid-template-columns:minmax(0,1fr); align-items:center; gap:8px; margin:0; padding:10px 12px calc(10px + env(safe-area-inset-bottom)); border:1px solid #4ade80; border-radius:12px 0 0; background:rgba(11,21,38,.98); overflow-wrap:anywhere; }
 .completed-filed-actions[hidden] { display:none; }
 .completed-filed-actions button { min-height:44px; min-width:0; }

frontend/dashboard.js

@@ -1353,6 +1353,19 @@
     panel: qs('#update-sheet .update-sheet-panel'),
     jump: qs('#jump-update-new-activity'),
   });
+  const mobileUpdateDetailNavigation = createMobileUpdateDetailNavigation({
+    root:qs('#update-sheet .update-sheet-panel'),
+    buttons:Object.fromEntries(Array.from(document.querySelectorAll('[data-update-section]')).map(button => [button.dataset.updateSection, button])),
+    targets:{
+      conversation:qs('#update-conversation'),
+      context:qs('#update-subject-context'),
+      reply:qs('#update-reply-workspace'),
+    },
+    replyComposer:qs('#update-reply'),
+    jumpToNewActivity:() => updateReadPosition.jump(),
+    prefersReducedMotion:() => window.matchMedia('(prefers-reduced-motion: reduce)').matches,
+  });
+  mobileUpdateDetailNavigation.start();
   const issueDetailPosition = createWorkDetailPosition({ panel: qs('#issue-sheet .issue-sheet-panel') });
   const pullDetailPosition = createWorkDetailPosition({ panel: qs('#pull-sheet .pull-sheet-panel') });
   const reviewDetailPosition = createWorkDetailPosition({ panel: qs('#review-sheet .review-sheet-panel') });
@@ -1391,6 +1404,7 @@
       void updateVoiceReply.open('update:' + item.notification_id);
       selectedUpdateDetail = null;
       updateReadPosition.open(String(item.notification_id));
+      mobileUpdateDetailNavigation.reset();
       updateMentions.dismiss();
       qs('#update-sheet').classList.add('open');
       qs('.update-more-actions').open = false;

frontend/index.html

@@ -1098,6 +1098,12 @@
       </div>
     </div>
     <div id="update-triage-progress" class="update-triage-progress small" aria-live="polite" hidden></div>
+    <nav class="mobile-update-detail-nav" aria-label="Update sections">
+      <button type="button" data-update-section="activity">New activity</button>
+      <button type="button" data-update-section="conversation">Conversation</button>
+      <button type="button" data-update-section="context">Subject context</button>
+      <button type="button" data-update-section="reply">Reply</button>
+    </nav>
     <div id="update-gesture-status" class="update-gesture-status small" aria-live="polite">Swipe right to keep unread or left to mark read. Buttons remain available.</div>
     <div id="update-sheet-status" class="small" aria-live="polite">Choose an update.</div>
     <button class="update-retry" id="retry-update-load" type="button" hidden>Retry loading update</button>
@@ -1105,18 +1111,20 @@
       <span class="pill" id="update-subject-type">Update</span>
       <span class="pill" id="update-subject-state"></span>
     </div>
-    <h2>Full conversation</h2>
-    <div id="update-comments"></div>
-    <button class="update-new-activity-jump" id="jump-update-new-activity" type="button" hidden>Jump to new activity</button>
-    <button class="conversation-more" id="load-older-update-comments" type="button" hidden>Load older messages</button>
-    <div id="update-conversation-status" class="small" aria-live="assertive"></div>
-    <button class="update-retry" id="retry-update-conversation" type="button" hidden>Retry conversation</button>
-    <button class="conversation-actions-retry" id="retry-update-comment-actions" type="button" hidden>Retry comment tools</button>
-    <details>
+    <section id="update-conversation" tabindex="-1">
+      <h2>Full conversation</h2>
+      <div id="update-comments"></div>
+      <button class="update-new-activity-jump" id="jump-update-new-activity" type="button" hidden>Jump to new activity</button>
+      <button class="conversation-more" id="load-older-update-comments" type="button" hidden>Load older messages</button>
+      <div id="update-conversation-status" class="small" aria-live="assertive"></div>
+      <button class="update-retry" id="retry-update-conversation" type="button" hidden>Retry conversation</button>
+      <button class="conversation-actions-retry" id="retry-update-comment-actions" type="button" hidden>Retry comment tools</button>
+    </section>
+    <details id="update-subject-context">
       <summary><h2>Subject context</h2></summary>
       <div class="update-sheet-content muted markdown-content" id="update-subject-body"></div>
     </details>
-    <section class="update-reply" aria-labelledby="update-reply-title">
+    <section class="update-reply" id="update-reply-workspace" aria-labelledby="update-reply-title">
       <h2 id="update-reply-title">Reply</h2>
       <label for="update-reply" class="small">Continue this issue or pull-request conversation</label>
       <textarea id="update-reply" maxlength="10000" placeholder="Write a reply"></textarea>
@@ -1549,6 +1557,7 @@
 <script src="static/push-notifications.js"></script>
 <script src="static/issue-filing-receipt.js"></script>
 <script src="static/mobile-issue-detail-nav.js"></script>
+<script src="static/mobile-update-detail-nav.js"></script>
 <script src="static/dashboard.js"></script>
 </body>
 </html>

frontend/mobile-update-detail-nav.js

@@ -0,0 +1,83 @@
+function createMobileUpdateDetailNavigation(options) {
+  const buttons = options.buttons || {};
+  const targets = options.targets || {};
+  const listeners = new Map();
+  const prefersReducedMotion = options.prefersReducedMotion || (() => false);
+  const targetNames = new Map(Object.entries(targets).map(([name, target]) => [target, name]));
+  let observer = null;
+
+  function select(name) {
+    Object.entries(buttons).forEach(([key, button]) => {
+      if (!button) return;
+      if (key === name) button.setAttribute('aria-current', 'location');
+      else button.removeAttribute('aria-current');
+    });
+  }
+
+  function navigate(name) {
+    if (name === 'activity') {
+      if (options.jumpToNewActivity) options.jumpToNewActivity();
+      select(name);
+      return true;
+    }
+    const target = targets[name];
+    if (!target) return false;
+    if (name === 'context') target.open = true;
+    target.scrollIntoView({
+      block:'start',
+      behavior:prefersReducedMotion() ? 'auto' : 'smooth',
+    });
+    if (name === 'reply' && options.replyComposer) {
+      options.replyComposer.focus({ preventScroll:true });
+    }
+    select(name);
+    return true;
+  }
+
+  function reset() {
+    if (targets.context) targets.context.open = false;
+    select('activity');
+  }
+
+  return {
+    start() {
+      Object.entries(buttons).forEach(([name, button]) => {
+        if (!button || listeners.has(button)) return;
+        const listener = event => {
+          event.preventDefault();
+          navigate(name);
+        };
+        listeners.set(button, listener);
+        button.addEventListener('click', listener);
+      });
+      reset();
+      const observe = options.observe || ((handler, observedTargets) => {
+        if (typeof IntersectionObserver === 'undefined') return null;
+        const instance = new IntersectionObserver(handler, {
+          root:options.root || null,
+          rootMargin:'-20% 0px -60% 0px',
+          threshold:[0, 0.25, 0.5, 0.75, 1],
+        });
+        observedTargets.forEach(target => instance.observe(target));
+        return instance;
+      });
+      observer = observe(entries => {
+        const visible = entries
+          .filter(entry => entry.isIntersecting && targetNames.has(entry.target))
+          .sort((left, right) => right.intersectionRatio - left.intersectionRatio)[0];
+        if (visible) select(targetNames.get(visible.target));
+      }, Array.from(targetNames.keys()).filter(Boolean));
+    },
+    stop() {
+      listeners.forEach((listener, button) => button.removeEventListener('click', listener));
+      listeners.clear();
+      if (observer) observer.disconnect();
+      observer = null;
+    },
+    navigate,
+    reset,
+    select,
+  };
+}
+
+if (typeof module !== 'undefined') module.exports = createMobileUpdateDetailNavigation;

frontend/service-worker.js

@@ -78,6 +78,7 @@ const SHELL = [
   BASE + 'static/issue-filing-review.js',
   BASE + 'static/issue-sheet.js',
   BASE + 'static/mobile-issue-detail-nav.js',
+  BASE + 'static/mobile-update-detail-nav.js',
   BASE + 'static/checklist-conflict.js',
   BASE + 'static/voice-transcript-store.js',
   BASE + 'static/voice-issue-capture.js',