feat(bar): idle-inhibit (caffeine) toggle — generated bar + summer-day parity (item 13 slice)

Summer-night's whole-swap bar had an idle_inhibitor the generated bar
lacked (reverse parity gap from the 2026-07-04 sweep). The generated
bar now carries it — 󰾪 click → 󰅶, warm tint while active, tooltips
saying what it holds — blocking hypridle's lock/display-off/suspend
for videos and presentations; state deliberately resets with the bar.
summer-day mirrors summer-night's module + CSS, and the keybinds
cheatsheet mentions the bar click (via keybinds.extra).

V1: rendered config has the module with correct glyphs, CSS rules
present, cheatsheet row renders. Inhibit behaviour needs a session →
V3 queued.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

themes/summer-day/waybar.css

@@ -44,6 +44,7 @@ window#waybar {
 
 #custom-launcher,
 #custom-recording,
+#idle_inhibitor,
 #clock,
 #clock-date,
 #workspaces,
@@ -116,6 +117,12 @@ window#waybar {
   padding-right: 23px;
 }
 
+#idle_inhibitor {
+    padding-left: 10px;
+    padding-right: 10px;
+    font-size: 20px;
+}
+
 /* Recording in progress: alert red; the module is also the stop button. */
 #custom-recording.recording {
   color: @red;