feat: resume interrupted Today sessions (#395)

frontend/dashboard.css

@@ -246,6 +246,7 @@ textarea { resize: vertical; min-height: 120px; }
 .find-work-action { min-height:44px; }
 .my-work-actions { display:flex; flex-wrap:wrap; gap:8px; }
 .start-work-session { min-height:44px; }
+.resume-today-session, .end-today-session { min-height:44px; }
 .work-session-nav { position:sticky; bottom:0; z-index:5; display:grid; grid-template-columns:1fr 1fr; gap:8px; margin-top:12px; padding:10px 4px; padding-bottom:calc(10px + env(safe-area-inset-bottom)); background:rgba(11,21,38,.98); border-top:1px solid #2a496e; }
 .work-session-nav[hidden] { display:none; }
 .work-session-nav [data-work-session-progress] { grid-column:1 / -1; text-align:center; }

frontend/dashboard.js

@@ -665,12 +665,30 @@
     openRoutedWork(item, null, { replace:true });
   }
 
+  const sessionCheckpoint = createWorkSessionCheckpoint({
+    storage: localStorage,
+    getLogin: () => confirmedOwnerLogin,
+    onError: () => {
+      qs('#my-work-action-status').textContent =
+        'Session recovery could not be saved on this device. You can keep working.';
+    },
+  });
+  function updateWorkSessionActions() {
+    const active = workSession.active();
+    qs('#start-work-session').hidden = active;
+    qs('#resume-today-session').hidden = active || !todayMyWork.length || !workSession.resumable();
+    qs('#end-today-session').hidden = !active;
+  }
+
   const workSession = createWorkSession({
     getItems: () => selectedWorkFilter === 'today' ? todayMyWork : activeMyWork,
     getFilter: () => selectedWorkFilter === 'today' ? 'all' : selectedWorkFilter,
     getMilestone: () => selectedWorkMilestone,
+    checkpoint: sessionCheckpoint,
+    checkpointEnabled: () => selectedWorkFilter === 'today',
     onOpen: openWorkSessionItem,
     onProgress: state => {
+      updateWorkSessionActions();
       document.querySelectorAll('.work-session-nav').forEach(nav => { nav.hidden = false; });
       document.querySelectorAll('[data-work-session-progress]').forEach(element => {
         element.textContent = 'Item ' + state.index + ' of ' + state.total;
@@ -686,6 +704,7 @@
       closeOpenWorkSheets();
       document.querySelectorAll('.work-session-nav').forEach(nav => { nav.hidden = true; });
       qs('#my-work-action-status').textContent = 'Work session complete.';
+      updateWorkSessionActions();
       qs('#start-work-session').focus();
     },
   });
@@ -1042,6 +1061,7 @@
     updateWorkPaginationControls();
     renderMyWork();
     if (reconcileSession && workSession.active()) workSession.reconcile();
+    updateWorkSessionActions();
   }
 
   function activeWorkStreams() {
@@ -3576,6 +3596,18 @@
     }
     workSession.start();
   });
+  qs('#resume-today-session').addEventListener('click', () => {
+    qs('[data-work-filter="today"]').click();
+    if (!workSession.resume()) {
+      qs('#my-work-action-status').textContent = 'Saved Today session is no longer available.';
+      updateWorkSessionActions();
+    }
+  });
+  qs('#end-today-session').addEventListener('click', () => {
+    workSession.end();
+    qs('#my-work-action-status').textContent = 'Today session ended. Your plan is unchanged.';
+    qs('#start-work-session').focus();
+  });
   document.querySelectorAll('[data-work-session-previous]').forEach(button =>
     button.addEventListener('click', () => workSession.previous())
   );

frontend/index.html

@@ -50,6 +50,8 @@
       <div class="my-work-actions">
         <button class="plan-today" id="plan-today" type="button">Plan Today</button>
         <button class="start-work-session" id="start-work-session" type="button">Start work</button>
+        <button class="resume-today-session" id="resume-today-session" type="button" hidden>Resume Today</button>
+        <button class="end-today-session" id="end-today-session" type="button" hidden>End session</button>
         <button class="find-work-action" id="find-work" type="button">Find work</button>
         <button class="new-issue" id="new-issue" type="button">New issue</button>
       </div>

frontend/my-work.js

@@ -472,10 +472,67 @@ function workIdentity(item) {
   return [kind, repository, number, notification].join(':');
 }
 
-function createWorkSession({ getItems, getFilter, getMilestone = () => 'all', onOpen, onProgress, onFinish }) {
+function createWorkSessionCheckpoint({
+  storage,
+  getLogin,
+  onError = () => {},
+  key = 'stackchain.today-session.v1',
+}) {
+  const login = () => String(getLogin() || '').trim();
+  let errorReported = false;
+  const reportError = error => {
+    if (errorReported) return;
+    errorReported = true;
+    onError(error);
+  };
+  const read = () => {
+    const owner = login();
+    if (!owner) return null;
+    try {
+      const value = JSON.parse(storage.getItem(key) || 'null');
+      if (value?.version !== 1 || value.login !== owner || typeof value.identity !== 'string' ||
+          !Number.isInteger(value.index) || value.index < 0) return null;
+      return value;
+    } catch (error) {
+      reportError(error);
+      return null;
+    }
+  };
+  return {
+    read,
+    save(identity, index) {
+      const owner = login();
+      if (!owner) return false;
+      try {
+        storage.setItem(key, JSON.stringify({ version:1, login:owner, identity, index }));
+        return true;
+      } catch (error) {
+        reportError(error);
+        return false;
+      }
+    },
+    clear() {
+      if (!read()) return false;
+      try {
+        storage.removeItem(key);
+        return true;
+      } catch (error) {
+        reportError(error);
+        return false;
+      }
+    },
+  };
+}
+
+function createWorkSession({
+  getItems, getFilter, getMilestone = () => 'all', checkpoint = null,
+  checkpointEnabled = () => true,
+  onOpen, onProgress, onFinish,
+}) {
   let currentIdentity = '';
   let currentIndex = -1;
   let running = false;
+  let durable = false;
 
   const queue = () => filterMyWork(getItems() || [], getFilter(), getMilestone());
   const report = (items, index) => onProgress({
@@ -485,9 +542,12 @@ function createWorkSession({ getItems, getFilter, getMilestone = () => 'all', on
     can_next: index < items.length - 1,
   });
   const finish = () => {
+    const clearCheckpoint = durable;
     running = false;
+    durable = false;
     currentIdentity = '';
     currentIndex = -1;
+    if (clearCheckpoint) checkpoint?.clear();
     onFinish();
     return false;
   };
@@ -495,6 +555,7 @@ function createWorkSession({ getItems, getFilter, getMilestone = () => 'all', on
     if (!items.length || index < 0 || index >= items.length) return finish();
     currentIndex = index;
     currentIdentity = workIdentity(items[index]);
+    if (durable) checkpoint?.save(currentIdentity, currentIndex);
     report(items, index);
     onOpen(items[index]);
     return true;
@@ -502,10 +563,23 @@ function createWorkSession({ getItems, getFilter, getMilestone = () => 'all', on
 
   return {
     active: () => running,
+    end: () => finish(),
+    resumable: () => Boolean(checkpoint?.read()),
+    resume() {
+      const saved = checkpoint?.read();
+      if (!saved) return false;
+      durable = true;
+      const items = queue();
+      if (!items.length) return finish();
+      running = true;
+      const exact = items.findIndex(item => workIdentity(item) === saved.identity);
+      return openAt(items, exact >= 0 ? exact : Math.min(saved.index, items.length - 1));
+    },
     start(item = null) {
       const items = queue();
       if (!items.length) return finish();
       running = true;
+      durable = Boolean(checkpoint && checkpointEnabled());
       const requested = item ? items.findIndex(candidate => workIdentity(candidate) === workIdentity(item)) : 0;
       return openAt(items, requested >= 0 ? requested : 0);
     },
@@ -612,6 +686,7 @@ if (typeof module !== 'undefined' && module.exports) {
   buildMyWork.filterMyWork = filterMyWork;
   buildMyWork.milestoneLanes = milestoneLanes;
   buildMyWork.createWorkSession = createWorkSession;
+  buildMyWork.createWorkSessionCheckpoint = createWorkSessionCheckpoint;
   buildMyWork.workIdentity = workIdentity;
   buildMyWork.replaceIssueLabels = replaceIssueLabels;
   buildMyWork.replaceIssueContent = replaceIssueContent;

frontend/service-worker.js

@@ -1,6 +1,6 @@
 const BASE = new URL('./', self.location.href).pathname;
 importScripts(BASE + 'static/background-issue-sync.js');
-const CACHE = 'stackchain-dashboard-shell-v59';
+const CACHE = 'stackchain-dashboard-shell-v60';
 const OUTAGE_STATUSES = new Set([500, 502, 503, 504]);
 const NAVIGATION_TIMEOUT_MS = self.__STACKCHAIN_NAVIGATION_TIMEOUT_MS || 4000;
 const SHELL = [