perf: lazy-load pull request workspace (Closes #541)

frontend/dashboard.js

@@ -269,11 +269,8 @@
     }
     return payload;
   }
-  const reviewController = createReviewController({ fetchJson: fetchReviewJson, storage: localStorage });
-  const wrapPreference = createReviewController.createWrapPreference({
-    storage: localStorage,
-    mobile: window.matchMedia('(max-width: 600px)').matches,
-  });
+  let reviewController = null;
+  let wrapPreference = null;
   const issueController = createIssueSheet({ fetchJson: fetchReviewJson, storage: localStorage });
   const issueAttachmentController = issueAttachment.mount({
     input: qs('#issue-attachment'),
@@ -438,7 +435,27 @@
     });
   }
   if (Object.values(sharedLaunch).some(Boolean)) await ensureIssueCapture();
-  const pullController = createPullSheet({ fetchJson: fetchReviewJson, storage: localStorage });
+  const pullWorkflowFeatures = createFeatureLoader({
+    document,
+    urls: {
+      'pull-workflow': document.querySelector('meta[name="stackchain-feature-pull-workflow"]')?.content || '',
+    },
+  });
+  let pullController = null;
+  async function ensurePullWorkflow(trigger = null) {
+    return await pullWorkflowFeatures.run('pull-workflow', {
+      trigger, status: qs('#my-work-action-status'), retryLabel:'Tap the work card to retry.',
+    }, () => {
+      if (!pullController) pullController = createPullSheet({ fetchJson: fetchReviewJson, storage: localStorage });
+      if (!reviewController) reviewController = createReviewController({ fetchJson: fetchReviewJson, storage: localStorage });
+      if (!wrapPreference) {
+        wrapPreference = createReviewController.createWrapPreference({
+          storage: localStorage,
+          mobile: window.matchMedia('(max-width: 600px)').matches,
+        });
+      }
+    });
+  }
   const draftInbox = createDraftInbox({ storage: localStorage, getCurrentLogin: () => activeFlushLogin });
   outboxCoordinator.subscribe(() => refreshMyWorkView());
   const offlineWorkStore = createOfflineWorkStore({ storage: localStorage, indexedDB:window.indexedDB });
@@ -456,8 +473,13 @@
     retry.hidden = status.failed === 0;
   }
   const offlineToday = createOfflineToday({
-    loadDetail: item => item.is_review ? reviewController.load(item) :
-      item.kind === 'pull' ? pullController.load(item) : issueController.load(item),
+    loadDetail: async item => {
+      if (item.is_review || item.kind === 'pull') {
+        if (!await ensurePullWorkflow()) throw new Error('Pull workspace is unavailable.');
+        return item.is_review ? reviewController.load(item) : pullController.load(item);
+      }
+      return issueController.load(item);
+    },
     loadSavedDetail: (login, item) => offlineWorkStore.loadDetail(login, item),
     saveDetail: (login, item, detail) => offlineWorkStore.saveDetail(login, item, detail),
     onStatus: renderOfflineTodayStatus,
@@ -2588,6 +2610,7 @@
 
   async function openPullSheet(item, trigger, offlineDetail = null) {
     if (!item) return;
+    if (!await ensurePullWorkflow(trigger)) return;
     if (!sameWorkTarget(selectedPull, item)) pullAttachmentController.clear();
     qs('#pull-review').inert = false;
     selectedPull = item;
@@ -3144,6 +3167,7 @@
   }
 
   async function openReviewSheet(item, trigger, cachedDetail = null) {
+    if (!item || !await ensurePullWorkflow(trigger)) return;
     selectedReview = item;
     reviewTrigger = trigger;
     offlineReview = Boolean(cachedDetail);

frontend/feature-loader.js

@@ -36,6 +36,7 @@ function createFeatureLoader({ document, urls, timeoutMs = 10000 }) {
   async function run(name, elements, callback) {
     const trigger = elements?.trigger;
     const status = elements?.status;
+    const retryLabel = elements?.retryLabel || 'Tap New issue to retry.';
     if (trigger) trigger.disabled = true;
     if (status) status.textContent = 'Loading ' + name.replace(/-/g, ' ') + '…';
     try {
@@ -45,8 +46,9 @@ function createFeatureLoader({ document, urls, timeoutMs = 10000 }) {
       return true;
     } catch (_error) {
       if (status) {
-        const label = name === 'issue-capture' ? 'Issue capture' : name.replace(/-/g, ' ');
-        status.textContent = label + ' could not load. Tap New issue to retry.';
+        const label = name === 'issue-capture' ? 'Issue capture' :
+          name === 'pull-workflow' ? 'Pull workspace' : name.replace(/-/g, ' ');
+        status.textContent = label + ' could not load. ' + retryLabel;
       }
       return false;
     } finally {