v1.0.20: fix button icons and surface user-fetch errors

- Remove stale idle.svg/running.svg from zip (were shadowing the PNG
  icons added in v1.0.15, causing old grey icons to show instead of
  the Aurora timer images)
- Fix package script to always delete and recreate zip so removed files
  don't persist across builds
- Show a clear error in the name dropdown when fetchUsers fails (e.g.
  Notion integration missing "Read user information" capability)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

com.pdma.notion-timer.sdPlugin/ui/property-inspector.html

@@ -127,6 +127,7 @@
         <option value="">— Select your name —</option>
       </select>
     </div>
+    <p id="userError" class="hint" style="color:#e57373;padding-left:0;"></p>
     <p class="hint">Shared across all buttons. Select once per device.</p>
     <p id="credStatus"></p>
     <hr class="divider">
@@ -304,9 +305,17 @@
         if (payload.version) {
           document.getElementById("versionText").textContent = "v" + payload.version;
         }
-        if (payload.users) {
+        if (payload.users !== undefined) {
           var savedUserId = document.getElementById("userId").value;
           populateUsers(payload.users, savedUserId);
+          var userErr = document.getElementById("userError");
+          if (payload.usersError) {
+            userErr.textContent = "Could not load names: " + payload.usersError;
+          } else if (payload.users.length === 0) {
+            userErr.textContent = "No users found — check the integration has \u201cRead user information\u201d enabled.";
+          } else {
+            userErr.textContent = "";
+          }
         }
         if (payload.error) {
           setStatus(payload.error, "error");