Fix wheel-photo squareness bug, native select popups, image-cycle crash

.bildbox.radbild lost to a same-specificity, later-declared .bildbox rule,
so the wheel photo stayed a full-width 4:3 box despite the earlier crop
fix - only which slice showed ever changed. Fixed with a compound selector
and moved "Montiert" to top-left to match the now-correctly-sized photo.

Native <select> popups had no color-scheme hint and rendered in the
browser's default light palette regardless of the app's dark theme -
this is what made "Modell" and other dropdowns flash bright white.

bildWeiter() (Mein Audi image-cycle tap) referenced a CSS class that was
never emitted (.platzhalter-datei vs. the real .platzhalter-aktion),
throwing and aborting before the page-dot indicator update - the photo
advanced but the dots never moved.

Merged the separate "Fahrzeugbilder" upload grid into "Bild der
Übersicht": pick a view from the existing dropdown, tap its preview to
upload/replace/delete - same generic popup plumbing, no new mechanism.
Removed the now-dead BILDER_UPLOAD_SLOTS/.bildgrid/.bildslot/.carfix.mini.

Back arrow changed from red to the neutral headline color, matching every
other navigation-color decision in this project.

Investigated but could not reproduce: user-reported "whole tab bar
disappears" when hiding labels. Traced the exact commit that added the
icon+label highlight and confirmed it's correctly scoped to :not(.ohne);
live DOM/computed-style testing across toggle, navigation, and both
mobile/desktop widths showed the tab bar staying visible throughout.
Left unchanged pending a repro from the user.

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

homeassistant/www/audi-dashboard-ios.css

@@ -26,6 +26,11 @@
   --line-strong:rgba(255,255,255,.24);
   --fg:#FFFFFF; --fg2:#BFC4CC; --fg3:#8E8E93;
   --ok:#30D158; --warn:#FFD60A; --bad:#FF453A;
+  /* Ohne diese Angabe rendert der Browser native Steuerelemente (Dropdown-
+     Aufklapp-Liste bei <select>, Scrollbars) in seiner Standard-Hellansicht,
+     egal wie dunkel die App selbst ist - das liess z. B. "Modell" beim
+     Aufklappen grell-weiss aufblitzen. Betrifft alle <select>-Felder. */
+  color-scheme: dark;
 }
 :host([data-theme="tag"]){
   --canvas:#F2F2F7;
@@ -38,6 +43,7 @@
   --ios-sep:rgba(60,60,67,.16);
   --ios-fill:rgba(120,120,128,.16);
   --tile-deckend:#FFFFFF;
+  color-scheme: light;
 }
 
 body{padding:0;background:var(--canvas)}
@@ -67,7 +73,10 @@ html,body{height:100%}
 .eyebrow{display:none}
 .title{font-size:22px;font-weight:400;letter-spacing:-.01em;line-height:1.2}
 .back{width:34px;height:34px;margin-left:-8px;justify-content:center}
-.back svg{width:22px;height:22px;color:var(--ios-tint)}
+/* Rot bleibt Akzent/destruktiv, nicht Navigationsfarbe (dieselbe Regel wie
+   bei den Aktions-Buttons und dem aktiven Menü-Icon) - derselbe neutrale Ton
+   wie die Kopfzeile selbst. */
+.back svg{width:22px;height:22px;color:var(--fg)}
 .sync{margin-top:3px;font-size:12.5px;color:var(--fg3)}
 .sync svg{width:13px;height:13px}
 .themebtn{width:36px;height:36px;border:0;background:var(--ios-fill);color:var(--fg2)}