admin: ui polish pass, thirty findings from the emil audit

selected states stop changing font weight, buttons gain a pressed scale and scoped 120ms transitions with a reduced-motion override, every loading and empty state reserves its height, charts measure before first paint, hit targets rise to the 44px enhanced target where layout permits, long domains clamp to two lines on an unpadded inner span, chips and name cells truncate, tabular figures on counts and time columns, a z-index layer scale replaces magic numbers and fixes the dialog-over-confirm tie, history's empty state gains a clear-filters action, page headings balance, font smoothing and color-scheme land on the html reset.

admin/src/features/configuration/ProtectionGroups.tsx

@@ -167,7 +167,9 @@ function GroupsMasterDetail({ groups, status }: { groups: Group[]; status: Confi
 				</nav>
 			</div>
 			{selected === undefined ? (
-				<p {...stylex.props(config.empty)}>No groups exist.</p>
+				<p {...stylex.props(config.empty)}>
+					{fileMode ? "No groups exist." : "No groups exist. Create one with the New group field."}
+				</p>
 			) : fileMode ? (
 				<GroupDetailReadOnly group={selected} />
 			) : (
@@ -432,7 +434,10 @@ function GroupRules({ group, editable }: { group: Group; editable: boolean }) {
 					return (
 						<>
 							{scoped.length === 0 ? (
-								<p {...stylex.props(config.empty)}>No allow or block rules for this group.</p>
+								<p {...stylex.props(config.empty)}>
+									No allow or block rules for this group.
+									{editable && " Add one below."}
+								</p>
 							) : (
 								<RulesTable rules={scoped} editable={editable} />
 							)}