feat(flow): circular library <-> output navigation

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: New1Direction

library.js

@@ -532,10 +532,29 @@ function openNote(repoId, btn) {
   panel.querySelector('.lc-note-save')?.addEventListener('click', saveNote);
 }
 
-function openRow(repoId) {
+// Forward path (library → output). Before opening a fresh output tab, focus an
+// already-open output tab for the same repo so re-clicking a card round-trips
+// instead of orphaning duplicate analysis tabs. Output tabs set their title to
+// `… {repoId} — RepoLens` (output-tab.js), which is what we match on — the random
+// session key never reaches the URL, so the title is the only stable repo signal.
+async function focusExistingOutputTab(repoId) {
+  try {
+    const tabs = await chrome.tabs.query({ url: chrome.runtime.getURL('output-tab.html') + '*' });
+    const existing = tabs.find((t) => typeof t.title === 'string' && t.title.includes(`${repoId} — RepoLens`));
+    if (!existing) return false;
+    await chrome.tabs.update(existing.id, { active: true });
+    await chrome.windows.update(existing.windowId, { focused: true });
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+async function openRow(repoId) {
   const cached = cacheByRepo.get(repoId);
-  if (cached) openCachedAnalysis(cached);
-  else openSource(repoId);
+  if (!cached) { openSource(repoId); return; }
+  if (await focusExistingOutputTab(repoId)) return;
+  openCachedAnalysis(cached);
 }
 
 function openSource(repoId) {

output-tab.js

@@ -2438,8 +2438,18 @@ document.getElementById('copy-url')?.addEventListener('click', async () => {
   await copyWithFlash(document.getElementById('copy-url'), url);
 });
 
-document.getElementById('open-library')?.addEventListener('click', () => {
-  chrome.tabs.create({ url: chrome.runtime.getURL('library.html') });
+// Return path (output → library): focus an existing Library tab if one is open,
+// otherwise open a fresh one. Mirrors background.js's focus-or-create idiom so the
+// library ↔ output round-trip never orphans duplicate Library tabs.
+document.getElementById('open-library')?.addEventListener('click', async () => {
+  const libUrl = chrome.runtime.getURL('library.html');
+  const [existing] = await chrome.tabs.query({ url: libUrl });
+  if (existing) {
+    await chrome.tabs.update(existing.id, { active: true });
+    await chrome.windows.update(existing.windowId, { focused: true });
+  } else {
+    chrome.tabs.create({ url: libUrl });
+  }
 });
 
 const CURRENT_VERSION = '3.0.0';