diff --git a/dashboard/app/dashboard/layout.tsx b/dashboard/app/dashboard/layout.tsx
index 0416274..d8c4bc7 100644
--- a/dashboard/app/dashboard/layout.tsx
+++ b/dashboard/app/dashboard/layout.tsx
@@ -17,6 +17,16 @@ export default async function DashboardLayout({
       <main className="relative z-1 flex-1">
         <PageTransition>{children}</PageTransition>
       </main>
+      <footer className="relative z-10 flex items-center justify-center border-t border-border bg-bg/95 px-6 py-3 backdrop-blur">
+        <a
+          href="https://github.com/BODMAT/worktrace"
+          target="_blank"
+          rel="noopener noreferrer"
+          className="text-[10px] font-bold tracking-widest text-muted transition-colors hover:text-cyan"
+        >
+          GITHUB · RELEASES
+        </a>
+      </footer>
     </div>
   );
 }
diff --git a/dashboard/app/dashboard/reports/api-key-modal.tsx b/dashboard/app/dashboard/reports/api-key-modal.tsx
index e50be5d..9025204 100644
--- a/dashboard/app/dashboard/reports/api-key-modal.tsx
+++ b/dashboard/app/dashboard/reports/api-key-modal.tsx
@@ -18,6 +18,9 @@ export function ApiKeyModal({ open, status, onClose, onSaved }: Props) {
   const [busy,  setBusy]  = useState(false);
   const [error, setError] = useState<string | null>(null);
 
+  const trimmed = value.trim();
+  const keyFormatOk = trimmed.startsWith("gsk_") && trimmed.length >= 20;
+
   useEffect(() => {
     const onKey = (e: KeyboardEvent) => { if (e.key === "Escape") onClose(); };
     window.addEventListener("keydown", onKey);
@@ -105,7 +108,9 @@ export function ApiKeyModal({ open, status, onClose, onSaved }: Props) {
                 className="mb-2 w-full rounded border border-border bg-bg px-2 py-1.5 text-xs text-text outline-none transition-colors focus:border-purple disabled:opacity-50"
               />
 
-              {error ? (
+              {trimmed.length > 0 && !trimmed.startsWith("gsk_") ? (
+                <p className="mb-2 text-[11px] text-pink">Key must start with gsk_</p>
+              ) : error ? (
                 <p className="mb-2 text-[11px] text-pink">{error}</p>
               ) : null}
 
@@ -135,7 +140,7 @@ export function ApiKeyModal({ open, status, onClose, onSaved }: Props) {
                 <button
                   type="button"
                   onClick={() => commit(value)}
-                  disabled={busy || value.trim().length < 8}
+                  disabled={busy || !keyFormatOk}
                   className="cursor-pointer rounded border border-cyan bg-cyan/10 px-3 py-1.5 text-[10px] font-bold tracking-widest text-cyan transition-colors hover:bg-cyan/20 disabled:cursor-not-allowed disabled:opacity-50"
                 >
                   {busy ? "SAVING…" : "SAVE"}
diff --git a/dashboard/app/dashboard/reports/report-form.tsx b/dashboard/app/dashboard/reports/report-form.tsx
index 7641167..2c0deee 100644
--- a/dashboard/app/dashboard/reports/report-form.tsx
+++ b/dashboard/app/dashboard/reports/report-form.tsx
@@ -47,7 +47,14 @@ function loadCache(key: string): CachedReport | null {
 }
 
 function saveCache(key: string, data: CachedReport): void {
-  try { localStorage.setItem(key, JSON.stringify(data)); } catch { /* quota */ }
+  try {
+    localStorage.setItem(key, JSON.stringify(data));
+  } catch (err) {
+    if (err instanceof DOMException && (err.name === "QuotaExceededError" || err.name === "NS_ERROR_DOM_QUOTA_REACHED")) {
+      throw err; // let caller notify the user
+    }
+    // other DOMExceptions are unexpected — swallow silently
+  }
 }
 
 function fmtCreatedAt(iso: string): string {
@@ -146,7 +153,11 @@ export function ReportForm({ userEmail }: { userEmail: string }) {
     try {
       const result = await generateReport(input);
       const createdAt = new Date().toISOString();
-      saveCache(reportCacheKey(userEmail, range, from, to), { result, createdAt });
+      try {
+        saveCache(reportCacheKey(userEmail, range, from, to), { result, createdAt });
+      } catch {
+        toast.error("Report generated but couldn't be cached — browser storage is full.");
+      }
       setStatus({ kind: "success", result, createdAt });
     } catch (err) {
       const message = err instanceof Error ? err.message : "Failed to generate report";
diff --git a/extension/src/background/index.ts b/extension/src/background/index.ts
index 941f714..5c20838 100644
--- a/extension/src/background/index.ts
+++ b/extension/src/background/index.ts
@@ -48,17 +48,20 @@ function isExpired(expiresAt: number): boolean {
   return Date.now() >= expiresAt - EXPIRY_BUFFER_MS;
 }
 
-function decodeEmail(jwt: string): string | null {
+function decodeJwtPayload(jwt: string): { email?: string; exp?: number } | null {
   try {
     const payloadB64 = jwt.split(".")[1];
     if (!payloadB64) return null;
-    const payload = JSON.parse(atob(payloadB64)) as { email?: string };
-    return payload.email ?? null;
+    return JSON.parse(atob(payloadB64)) as { email?: string; exp?: number };
   } catch {
     return null;
   }
 }
 
+function decodeEmail(jwt: string): string | null {
+  return decodeJwtPayload(jwt)?.email ?? null;
+}
+
 // ─── Google OAuth ──────────────────────────────────────────────────────────────
 
 async function launchGoogleOAuth(): Promise<string> {
@@ -101,9 +104,9 @@ async function exchangeForJWT(googleIdToken: string): Promise<StoredAuth> {
   }
 
   const { token } = await res.json() as { token: string };
-  const payloadB64 = token.split(".")[1] ?? "";
-  const { exp } = JSON.parse(atob(payloadB64)) as { exp: number };
-  return { jwt: token, jwtExpiresAt: exp * 1000 };
+  const payload = decodeJwtPayload(token);
+  if (!payload?.exp) throw new Error("JWT missing exp claim");
+  return { jwt: token, jwtExpiresAt: payload.exp * 1000 };
 }
 
 // ─── Core ──────────────────────────────────────────────────────────────────────
@@ -163,6 +166,17 @@ async function tryEndDbSession(dbSessionId: string): Promise<void> {
   }
 }
 
+// ─── Music helpers ────────────────────────────────────────────────────────────
+
+const TRACK_SOURCE_DOMAINS: Record<TrackInfo["source"], string> = {
+  "youtube-music": "music.youtube.com",
+  "soundcloud":    "soundcloud.com",
+};
+
+async function isTrackBlocked(track: TrackInfo): Promise<boolean> {
+  return isDomainBlocked(`https://${TRACK_SOURCE_DOMAINS[track.source]}`);
+}
+
 // ─── Music: pull track from active tab ────────────────────────────────────────
 
 // Returns current playbackTime from the music tab without any side effects.
@@ -204,10 +218,7 @@ async function queryActiveTabForTrack(): Promise<TrackInfo | null> {
     const track = await chrome.tabs.sendMessage(tab.id, { type: "TRACK_REQUEST" }) as TrackInfo | null;
     if (track) {
       // Blocklist check before storing or persisting to DB
-      const sourceUrl = `https://${
-        track.source === "youtube-music" ? "music.youtube.com" : "soundcloud.com"
-      }`;
-      const blocked = await isDomainBlocked(sourceUrl);
+      const blocked = await isTrackBlocked(track);
       if (blocked) return null;
 
       await chrome.storage.local.set({ currentTrack: track });
@@ -355,7 +366,11 @@ chrome.runtime.onMessage.addListener(
             session: { ...session, elapsedMs: getElapsedMs(session) },
           });
           // Fire-and-forget DB session creation — retried by sync alarm if it fails
-          if (!session.dbSessionId) void ensureDbSession();
+          if (!session.dbSessionId) {
+            ensureDbSession().catch((err) =>
+              console.warn("[worktrace] ensureDbSession failed:", err),
+            );
+          }
         })
         .catch((err: unknown) =>
           sendResponse({
@@ -494,13 +509,8 @@ chrome.runtime.onMessage.addListener(
       const track = message.payload;
 
       // Background-level blocklist check: second line of defence after content script
-      // Derive the domain from the known source → hostname mapping
-      const trackSourceDomain: Record<TrackInfo["source"], string> = {
-        "youtube-music": "music.youtube.com",
-        "soundcloud":    "soundcloud.com",
-      };
       void (async () => {
-        const blocked = await isDomainBlocked(`https://${trackSourceDomain[track.source]}`);
+        const blocked = await isTrackBlocked(track);
         if (blocked) return;
 
         void chrome.storage.local.set({ currentTrack: track });
@@ -620,6 +630,9 @@ chrome.runtime.onMessage.addListener(
       return true;
     }
 
+    // Exhaustiveness guard — TypeScript compile error if a new message type is added without a handler
+    const _exhaustive: never = message;
+    void _exhaustive;
     return false;
   },
 );
diff --git a/extension/src/background/sync.ts b/extension/src/background/sync.ts
index 467def8..e44c319 100644
--- a/extension/src/background/sync.ts
+++ b/extension/src/background/sync.ts
@@ -21,6 +21,13 @@ let apiFetchFn:        ApiFetch        | null = null;
 let ensureDbSessionFn: EnsureDbSession | null = null;
 let checkAuthFn:       CheckAuth       | null = null;
 
+// Re-entry guard: the 30s alarm and the inline SESSION_STOP flush can overlap.
+// Without this, two concurrent flushes read the same queue, POST the same
+// events (event.create has no idempotency key → permanent duplicates), and
+// race on writing `remaining` back. The SW is single-threaded, so a synchronous
+// check before the first await is sufficient to serialise.
+let flushing = false;
+
 export function initSync(deps: {
   apiFetch:        ApiFetch;
   ensureDbSession: EnsureDbSession;
@@ -56,70 +63,81 @@ async function setStatus(patch: Partial<SyncStatus>): Promise<void> {
 export async function flush(): Promise<void> {
   if (!apiFetchFn || !ensureDbSessionFn || !checkAuthFn) return;
 
-  // Skip flush entirely if the user is not authenticated — avoids ERR_CONNECTION_REFUSED spam
-  const isAuth = await checkAuthFn();
-  if (!isAuth) return;
-
-  const session = await getSession();
-  if (!session) return;
-
-  const dbSessionId = session.dbSessionId ?? (await ensureDbSessionFn());
-  if (!dbSessionId) {
-    await setStatus({ lastError: "DB session not available" });
-    return;
-  }
-
-  const r       = await chrome.storage.local.get(PENDING_KEY);
-  const queue   = (r[PENDING_KEY] as PendingEvent[] | undefined) ?? [];
-  if (queue.length === 0) return;
-
-  const batch     = queue.slice(0, BATCH_SIZE);
-  let   sentCount = 0;
-  let   lastError: string | null = null;
-
-  for (let i = 0; i < batch.length; i++) {
-    const event = batch[i]!;
-    let res: Response;
-    try {
-      res = await apiFetchFn("/api/v1/events", {
-        method: "POST",
-        body:   JSON.stringify({ ...event, sessionId: dbSessionId }),
-      });
-    } catch (err) {
-      // Network error — keep this event and everything after it for the next flush
-      lastError = err instanceof Error ? err.message : "Network error";
-      break;
-    }
-
-    if (res.ok) {
-      sentCount++;
-      continue;
+  // Bail synchronously if another flush is already in flight (see `flushing` above).
+  if (flushing) return;
+  flushing = true;
+  try {
+    // Skip flush entirely if the user is not authenticated — avoids ERR_CONNECTION_REFUSED spam
+    const isAuth = await checkAuthFn();
+    if (!isAuth) return;
+
+    const session = await getSession();
+    if (!session) return;
+
+    const dbSessionId = session.dbSessionId ?? (await ensureDbSessionFn());
+    if (!dbSessionId) {
+      await setStatus({ lastError: "DB session not available" });
+      return;
     }
 
-    if (res.status === 401) {
-      // Token rotated/expired — stop, queue waits for next login
-      lastError = "Unauthorized — please sign in again";
+    const r       = await chrome.storage.local.get(PENDING_KEY);
+    const queue   = (r[PENDING_KEY] as PendingEvent[] | undefined) ?? [];
+    if (queue.length === 0) return;
+
+    const batch     = queue.slice(0, BATCH_SIZE);
+    let   sentCount = 0;
+    let   lastError: string | null = null;
+
+    for (let i = 0; i < batch.length; i++) {
+      const event = batch[i]!;
+      let res: Response;
+      try {
+        res = await apiFetchFn("/api/v1/events", {
+          method: "POST",
+          body:   JSON.stringify({ ...event, sessionId: dbSessionId }),
+        });
+      } catch (err) {
+        // Network error — keep this event and everything after it for the next flush
+        lastError = err instanceof Error ? err.message : "Network error";
+        break;
+      }
+
+      if (res.ok) {
+        sentCount++;
+        continue;
+      }
+
+      if (res.status === 401) {
+        // Token rotated/expired — stop, queue waits for next login
+        lastError = "Unauthorized — please sign in again";
+        break;
+      }
+
+      if (res.status >= 400 && res.status < 500) {
+        // Poisonous payload — drop it, keep going so it can't block the queue
+        sentCount++;
+        lastError = `Dropped invalid event (HTTP ${String(res.status)})`;
+        continue;
+      }
+
+      // 5xx — retry next alarm
+      lastError = `Server error (HTTP ${String(res.status)})`;
       break;
     }
 
-    if (res.status >= 400 && res.status < 500) {
-      // Poisonous payload — drop it, keep going so it can't block the queue
-      sentCount++;
-      lastError = `Dropped invalid event (HTTP ${String(res.status)})`;
-      continue;
+    if (sentCount > 0) {
+      // Re-read the queue: events may have been appended by content scripts
+      // while we were awaiting the network. Only drop what we actually sent.
+      const fresh     = await chrome.storage.local.get(PENDING_KEY);
+      const current   = (fresh[PENDING_KEY] as PendingEvent[] | undefined) ?? [];
+      const remaining = current.slice(sentCount);
+      await chrome.storage.local.set({ [PENDING_KEY]: remaining });
     }
-
-    // 5xx — retry next alarm
-    lastError = `Server error (HTTP ${String(res.status)})`;
-    break;
+    await setStatus({
+      lastSyncedAt: sentCount > 0 ? Date.now() : (await getStatus()).lastSyncedAt,
+      lastError,
+    });
+  } finally {
+    flushing = false;
   }
-
-  if (sentCount > 0) {
-    const remaining = queue.slice(sentCount);
-    await chrome.storage.local.set({ [PENDING_KEY]: remaining });
-  }
-  await setStatus({
-    lastSyncedAt: sentCount > 0 ? Date.now() : (await getStatus()).lastSyncedAt,
-    lastError,
-  });
 }
diff --git a/extension/src/popup/index.html b/extension/src/popup/index.html
index 9477633..28db512 100644
--- a/extension/src/popup/index.html
+++ b/extension/src/popup/index.html
@@ -14,7 +14,7 @@
         <div class="popup__logo">
           <span class="popup__logo-icon">⬡</span>
           <div class="popup__logo-stack">
-            <span class="popup__logo-text">WORKTRACE</span>
+            <a href="https://worktrace-ecru.vercel.app" class="popup__logo-text" target="_blank" rel="noopener noreferrer">WORKTRACE</a>
             <span class="popup__user-email" id="user-email" hidden></span>
           </div>
         </div>
diff --git a/extension/src/popup/popup.css b/extension/src/popup/popup.css
index 8b438c5..16591e4 100644
--- a/extension/src/popup/popup.css
+++ b/extension/src/popup/popup.css
@@ -67,6 +67,7 @@ body {
   font-weight: 700;
   color: var(--c-cyan);
   text-shadow: 0 0 6px color-mix(in srgb, var(--c-cyan) 60%, transparent);
+  text-decoration: none;
 }
 
 .popup__user-email {