Move frame name/mode into the page header; Calendar gets its own tab

Frame name (pencil-icon inline edit) and the Photos/Calendar mode
selector now live in the page header, shared across all four per-frame
pages instead of being buried in the Configuration form -- so renaming
a frame or flipping its mode no longer requires navigating to a
specific tab first.

Calendar settings move out of a conditionally-hidden card on the
Configuration tab into their own dedicated tab (new /frames/{id}/
calendar route), visually greyed out when the frame is in Photos mode
but still fully usable so calendar settings can be configured ahead of
switching modes. Also wires the week-start setting into the UI for the
first time (the column/backend support landed earlier but had no
control anywhere).

server/app/static/theme.css

@@ -468,6 +468,35 @@ code {
 }
 .tabs a:hover { color: var(--text); }
 .tabs a.active { color: var(--accent); border-bottom-color: var(--accent); font-weight: 600; }
+.tabs a.tab-disabled { opacity: 0.45; }
+.tabs a.tab-disabled:hover { opacity: 0.7; }
+
+.frame-name-view { display: inline-flex; align-items: center; gap: 6px; }
+.frame-name-pencil {
+  background: none;
+  border: none;
+  box-shadow: none;
+  cursor: pointer;
+  font-size: 14px;
+  line-height: 1;
+  padding: 4px;
+  margin: 0;
+  opacity: 0.55;
+  color: var(--text);
+  transition: opacity .12s ease, background-color .12s ease;
+}
+.frame-name-pencil:hover { opacity: 1; background: var(--surface-alt); border-radius: 6px; }
+.frame-name-edit { display: inline-flex; align-items: center; gap: 6px; }
+.frame-name-edit input {
+  width: auto;
+  margin-top: 0;
+  padding: 5px 8px;
+  font-size: 15px;
+  font-weight: 700;
+}
+.frame-name-edit button { margin-top: 0; }
+
+.frame-mode-select { width: auto; margin-top: 0; padding: 7px 10px; font-size: 13px; font-weight: 600; }
 
 .control-banner {
   display: flex;