Add themed widgets, calendar, and Open WebUI chat to the dashboard

- Apply GTK-like color scheme (dark greys, #f76b2f accent) across
  cards, buttons, glows and category colors
- Service cards use the official logo icons; Netbird card shows live
  reachability + latency instead of a separate top widget
- Top widgets: Today (calendar events with in-progress highlighting),
  Git activity (3 rows visible, scrollable), GPU with live ROCm stats
  and loaded Ollama models incl. GPU/CPU split
- Open WebUI card: inline prompt line with model selection
- Calendar section grouping events by day below the services
- data.json fetch with boot retry; GPU/Ollama poll every 5 s
- Today entries wrap long titles; README documents widgets,
  environment variables and the .env secrets pattern

index.html

@@ -51,10 +51,60 @@
         </div>
       </header>
 
+      <section class="widgets" id="widgets" aria-label="Live widgets">
+        <article class="widget widget-calendar" id="widget-calendar">
+          <div class="widget-head">
+            <div class="widget-icon" aria-hidden="true">📅</div>
+            <span class="widget-title">Today</span>
+          </div>
+          <div class="widget-body" id="today-events">
+            <p class="widget-loading">Loading…</p>
+          </div>
+        </article>
+
+        <article class="widget widget-git" id="widget-git">
+          <div class="widget-head">
+            <div class="widget-icon" aria-hidden="true">🐙</div>
+            <span class="widget-title">Git activity</span>
+          </div>
+          <div class="widget-body" id="git-stats">
+            <p class="widget-loading">Loading…</p>
+          </div>
+        </article>
+
+        <article class="widget widget-gpu" id="widget-gpu">
+          <div class="widget-head">
+            <div class="widget-icon" aria-hidden="true">🖥️</div>
+            <span class="widget-title">GPU</span>
+          </div>
+          <div class="widget-body">
+            <div id="gpu-stats">
+              <p class="widget-loading">Loading…</p>
+            </div>
+            <div class="ollama-block">
+              <div class="ollama-label">Ollama</div>
+              <div id="ollama-stats">
+                <p class="widget-loading">Loading…</p>
+              </div>
+            </div>
+          </div>
+        </article>
+      </section>
+
       <main id="app">
         <!-- sections rendered by script.js -->
       </main>
 
+      <section class="calendar-section" aria-labelledby="calendar-title">
+        <h2 id="calendar-title" class="section-title">
+          Calendar
+          <span class="count" id="calendar-count">0</span>
+        </h2>
+        <div id="calendar" class="calendar">
+          <p class="calendar-loading">Loading calendar…</p>
+        </div>
+      </section>
+
       <footer class="footer">
         <span id="stats"></span>
       </footer>