[feat](trx-frontend-http): give the Tools destinations page titles

Recorder stated its name; Statistics, Settings and About did not, so one
page in eight carried a title.  The class it used, section-heading, had
no rule behind it either, leaving even that title as a default h2.

Which way to unify follows from the navigation change.  The tab strip
highlights the destination you are on, so Radio, Bookmarks, Digital modes
and Map already say where you are and a title would repeat the strip
while costing vertical space the spectrum wants.  The four destinations
behind Tools get no such highlight — the strip looks the same on all of
them — so those are exactly the pages that have to name themselves.

Give the three that were missing a heading, and style section-heading so
all four match.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GdyUjuXejCEfiub675z6cz
Signed-off-by: Stan Grams <sjg@haxx.space>

src/trx-client/trx-frontend/trx-frontend-http/assets/web/index.html

@@ -1051,6 +1051,7 @@ SPDX-License-Identifier: GPL-2.0-or-later
       </template>
     </div>
     <div id="tab-statistics" class="tab-panel" style="display:none;">
+      <h2 class="section-heading">Statistics</h2>
       <template id="tmpl-statistics">
       <div class="stats-controls">
         <div class="stats-control-group">
@@ -1191,6 +1192,7 @@ SPDX-License-Identifier: GPL-2.0-or-later
       </section>
     </div>
     <div id="tab-settings" class="tab-panel" style="display:none;">
+      <h2 class="section-heading">Settings</h2>
       <div class="sub-tab-bar">
         <button class="sub-tab active" data-subtab="settings-scheduler">Scheduler</button>
         <button class="sub-tab" data-subtab="settings-background-decode">Background Decode</button>
@@ -1486,6 +1488,7 @@ SPDX-License-Identifier: GPL-2.0-or-later
       </div>
     </div>
     <div id="tab-about" class="tab-panel" style="display:none;">
+      <h2 class="section-heading">About</h2>
       <div id="auth-badge" style="display:none; margin-bottom: 1rem; padding: 0.5rem; background: var(--bg-secondary); border-radius: 0.25rem; color: var(--text-muted); font-size: 0.85rem;">Authenticated as: <strong id="auth-role-badge">--</strong></div>
       <template id="tmpl-about">
       <div class="sub-tab-bar">