feat: live presence, delivery-tick sync, brand rollout, call fixes, desktop 0.1.3

Live presence (fixes stale in-call/status until refresh — impossible in apps):
- server broadcasts a user's status over the chat socket on connect/disconnect, call
  join/leave, and status change (chat.js broadcastPresence; signaling + routes hooks).
- client onPresence() updates the contact dot + open-chat header live.

Chat delivery ticks (#6): chat-list row now mirrors the thread (delivered→double grey,
read→blue) via a new 'with' field on the delivered relay + onChatRead/onChatDelivered.

Call fixes: no bogus 'host handed over' when a 1:1 call ends (leaveMeeting forced);
branded call-connecting + chat-thread loaders; header subtitle tracks live call state.

Notifications: web notify + sw.js use sender/group DP + brand icon (not old wordmark);
desktop shell drops Web Push so only the single native toast fires (#5).

Brand: master icon/splash/loaders wired everywhere (PWA/favicon/apple-touch/.ico),
branded login (blue + gold CTA), branded toasts (BZToast) on all pages, Electron splash.

Desktop: dev auto-targets localhost (packaged→prod); version 0.1.3 with new multi-size
icon; dropped unused node-notifier; removed home-mockup.html.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

server/public/loaders/loader-orbit-dark.svg

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+</svg>

server/public/loaders/loader-orbit.svg

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+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100" width="64" height="64" role="img" aria-label="Loading">
+  <circle cx="50" cy="50" r="34" fill="none" stroke="#1F3B73" stroke-width="9" stroke-linecap="round" stroke-dasharray="165 300" transform="rotate(38 50 50)"/>
+  <g><circle cx="84" cy="50" r="7" fill="#FFC708"/>
+    <animateTransform attributeName="transform" type="rotate" from="0 50 50" to="360 50 50" dur="1.1s" repeatCount="indefinite"/></g>
+</svg>

server/public/loaders/loader-ring.svg

@@ -0,0 +1,6 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 50 50" width="50" height="50" role="img" aria-label="Loading">
+  <circle cx="25" cy="25" r="20" fill="none" stroke="#1F3B73" stroke-opacity="0.16" stroke-width="5"/>
+  <path fill="none" stroke="#FFC708" stroke-width="5" stroke-linecap="round" d="M25 5 A20 20 0 0 1 45 25">
+    <animateTransform attributeName="transform" type="rotate" from="0 25 25" to="360 25 25" dur="0.8s" repeatCount="indefinite"/>
+  </path>
+</svg>