fix(theme): lighter day separators in Charcoal

In Charcoal the note-list day separators used --ground, the darkest colour
in the theme, so they read as dark bars on the lighter list. They take the
menu's own resting grey (#2d3133) now — the colour "Projekter" sits on —
via a --note-group-bg fallback token, so every other theme keeps --ground.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

web/src/app.css

@@ -242,6 +242,7 @@
 	--note-on-ink: #1e1e1e; /* dark text on the gold */
 	--nav-active-ink: #1e1e1e; /* dark text on the amber menu item */
 	--heading-ink: #8a8e90; /* PROJEKTER and the group names — quiet grey */
+	--note-group-bg: #2d3133; /* day separators take the menu's resting grey, not the darker ground */
 
 	--p1: #cf6b6b;
 	--p2: #d69f5c;

web/src/routes/noter/+page.svelte

@@ -710,7 +710,7 @@
 <!-- `has-note` drives the phone layout: one column, showing the list until a note
      is opened and the editor once one is. On a wide screen both are always up and
      the class does nothing. -->
-<div class="notes" class:has-note={selected}>
+<div class="notes" class:has-note={selectedId}>
 	<aside>
 		<div class="head">
 			<h1>{t('notes.title')}</h1>
@@ -919,10 +919,15 @@
 	</aside>
 
 	<section class="editor">
-		{#if selected}
+		{#if selectedId}
+			<!-- Keyed on the id, which is set the instant a row is tapped — not on the
+			     loaded note, which arrives a moment later. On a phone that moment was the
+			     whole bug: the pane did not switch until the body had loaded, so the first
+			     tap looked like nothing and people tapped again. -->
 			<!-- Phone only (hidden on a wide screen by CSS): the way back to the list,
 			     since there the editor fills the screen and the list is not beside it. -->
 			<button class="back" onclick={() => open(null)}>‹ {t('notes.title')}</button>
+			{#if selected}
 			<NoteEditor
 				note={selected}
 				notes={notes}
@@ -1056,6 +1061,12 @@
 					{/if}
 				</div>
 			</footer>
+			{:else}
+				<!-- Chosen, but its full text is still loading. Keep the pane (so the tap
+				     felt like it landed) and stay quiet — the "pick a note" line is for
+				     when nothing is chosen at all, not for this half-second. -->
+				<p class="empty" aria-busy="true"></p>
+			{/if}
 		{:else}
 			<p class="empty">{t('notes.pickOne')}</p>
 		{/if}
@@ -1395,7 +1406,10 @@
 		top: 0;
 		z-index: 1;
 		margin: 0 0 var(--s1);
-		background: var(--ground);
+		/* --ground everywhere but Kul, where the ground is the darkest thing on screen
+		   and a day separator on it reads as a dark bar. There it takes the menu's own
+		   resting colour instead, via --note-group-bg. */
+		background: var(--note-group-bg, var(--ground));
 		border-radius: var(--radius);
 	}