archive: replace toolbar with a 220px split sidebar (camera list + calendar)

The player-frame toolbar (camera <select> + date input) is removed. Archive
main is now a row: a 220px sidebar split in half by height — the top half is
a scrollable clickable camera list, the bottom half holds the date input plus
a new inline month calendar (prev/next month, today + selected highlight,
Monday-first). Picking a camera or a day loads that day's recordings. The
player and DVR timeline move into an .arch-content column on the right.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/archive.html

@@ -16,16 +16,19 @@
     </aside>
 
     <main class="archive-main">
-      <div class="toolbar">
-        <label class="muted">Камера:</label>
-        <select id="cam-select"></select>
-        <label class="muted">Дата:</label>
-        <input type="date" id="date">
+      <aside class="arch-side">
+        <div class="arch-cams" id="arch-cams"></div>
+        <div class="arch-date">
+          <input type="date" id="date" class="arch-dateinput">
+          <div class="arch-cal" id="calendar"></div>
+        </div>
+      </aside>
+      <div class="arch-content">
+        <div class="player-wrap" id="player">
+          <div class="hint">Кликните по таймлайну ниже, чтобы смотреть запись</div>
+        </div>
+        <div class="timeline" id="timeline"></div>
       </div>
-      <div class="player-wrap" id="player">
-        <div class="hint">Кликните по таймлайну ниже, чтобы смотреть запись</div>
-      </div>
-      <div class="timeline" id="timeline"></div>
     </main>
   </div>