Improve Mobile UI for dialogs and action dropdowns (#16222)

* fix: Always show conversation item actions

* feat: Improve Alert Dialog and Dialog mobile UI

* feat: Add settings reset to default confirmation

* fix: Close Edit dialog on save

* chore: update webui build output

* webui: implement proper z-index system and scroll management

- Add CSS variable for centralized z-index control
- Fix dropdown positioning with Settings dialog conflicts
- Prevent external scroll interference with proper event handling
- Clean up hardcoded z-index values for maintainable architecture

* webui: ensured the settings dialog enforces dynamic viewport height on mobile while retaining existing desktop sizing overrides

* feat: Use `dvh` instead of computed px height for dialogs max height on mobile

* chore: update webui build output

* feat: Improve Settings fields UI

* chore: update webui build output

* chore: update webui build output

---------

Co-authored-by: Pascal <admin@serveurperso.com>

tools/server/webui/src/lib/components/app/misc/ActionDropdown.svelte

@@ -37,6 +37,7 @@
 <DropdownMenu.Root bind:open>
 	<DropdownMenu.Trigger
 		class="flex h-6 w-6 cursor-pointer items-center justify-center rounded-md p-0 text-sm font-medium transition-colors hover:bg-accent hover:text-accent-foreground focus:bg-accent focus:text-accent-foreground focus:outline-none disabled:pointer-events-none disabled:opacity-50 data-[state=open]:bg-accent data-[state=open]:text-accent-foreground {triggerClass}"
+		onclick={(e) => e.stopPropagation()}
 	>
 		{#if triggerTooltip}
 			<Tooltip.Root delayDuration={TOOLTIP_DELAY_DURATION}>
@@ -53,7 +54,7 @@
 		{/if}
 	</DropdownMenu.Trigger>
 
-	<DropdownMenu.Content {align} class="z-999 w-48">
+	<DropdownMenu.Content {align} class="z-[999999] w-48">
 		{#each actions as action, index (action.label)}
 			{#if action.separator && index > 0}
 				<DropdownMenu.Separator />