picker demos: footer composition switches + popover closed by default

Two follow-ups from user feedback:

(1) User: 'en los demos no existen para definir las propiedades y
visibilidad del pie y los botones' — after the previous refactor that
moved visibility from props to composition, the demos lost their UI
switches and there was no way to toggle the parts on/off.

Restored toggles but with the correct semantics: the switches now
decide whether each part is INCLUDED in the markup, not whether the
part renders internally. Composition first, demo UX second.

- Both demos: new state vars showFooter / showClear / showCancel /
  showClose (default all true).
- New `{#snippet pickerFooter()}` snippet that renders
  <Footer><Clear/><Cancel/><Close/></Footer> with {#if show*}
  guards on each child. Rendered once via {@render pickerFooter()}
  at the end of every calendar branch (Calendar / MonthView /
  YearView for single; the rangeCalendar for range).
- New 'footer' control row with 4 switches per demo, labelled with
  the structural intent ('compose parts inside <Footer>').

(2) User: 'el popover del calendar aparece, eso es un error' — the
previous commit defaulted open=true on both demos so the new Footer
was visible at first paint. That conflicted with the natural flow
(user expects to click the trigger to open). Reverted to open=false
by default.

Also removed the auto-reopen $effect that re-opened the popover
whenever `kind` changed. The chip click can close the popover via
outside-click in inline mode; the user re-opens deliberately. No more
magic.

Verification: 0 type errors, 67/67 component:audit PASS.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

web/routes/uix/components/date-picker/+page.svelte

@@ -47,7 +47,7 @@
 	let value = $state<DateValue | undefined>(delivery);
 	let valueInput = $state(toDateInput(delivery));
 	let placeholder = $state<DateValue>(delivery);
-	let open = $state(true);
+	let open = $state(false);
 	let minInput = $state(toDateInput(defaultMin));
 	let maxInput = $state(toDateInput(defaultMax));
 	let required = $state(true);
@@ -56,6 +56,16 @@
 	let closeOnDateSelect = $state(false);
 	let mode = $state<'inline' | 'modal'>('inline');
 	let kind = $state<'date' | 'month' | 'year'>('date');
+
+	// Footer composition demo toggles. Visibility is purely structural:
+	// the switches decide whether each part is INCLUDED in the markup,
+	// not whether the part itself decides to render. Omit the part →
+	// nothing renders. Include it → it always renders.
+	let showFooter = $state(true);
+	let showClear = $state(true);
+	let showCancel = $state(true);
+	let showClose = $state(true);
+
 	let disableDaysOutsideMonth = $state(true);
 	let fixedWeeks = $state(false);
 	let pagedNavigation = $state(false);
@@ -216,14 +226,6 @@
 		valueInput = value ? toDateInput(value) : '';
 	});
 
-	// Re-open the popover whenever the kind changes — clicking the kind
-	// chip is outside the popover and closes it in inline mode. The demo
-	// wants the new view (Calendar / MonthView / YearView) visible
-	// immediately so the change is observable.
-	$effect(() => {
-		void kind;
-		open = true;
-	});
 
 	$effect(() => {
 		const el = stageRef;
@@ -467,18 +469,8 @@
 						<DatePicker.Content align="end" sideOffset={10} collisionPadding={12}>
 							{#if kind === 'year'}
 								<DatePicker.YearView />
-								<DatePicker.Footer>
-									<DatePicker.Clear />
-									<DatePicker.Cancel />
-									<DatePicker.Close />
-								</DatePicker.Footer>
 							{:else if kind === 'month'}
 								<DatePicker.MonthView />
-								<DatePicker.Footer>
-									<DatePicker.Clear />
-									<DatePicker.Cancel />
-									<DatePicker.Close />
-								</DatePicker.Footer>
 							{:else}
 								<DatePicker.Calendar>
 									{#snippet children(args: DatePickerCalendarSnippetProps)}
@@ -486,6 +478,7 @@
 									{/snippet}
 								</DatePicker.Calendar>
 							{/if}
+							{@render pickerFooter()}
 						</DatePicker.Content>
 					</DatePicker.Portal>
 				</DatePicker>
@@ -653,6 +646,31 @@
 						{/each}
 					</span>
 				</label>
+				<label data-uix-control>
+					<span data-uix-control-label
+						>footer <span data-uix-control-hint>compose parts inside &lt;Footer&gt;</span></span
+					>
+					<span data-uix-switch
+						><input type="checkbox" bind:checked={showFooter} /><span data-uix-switch-label
+							>Footer</span
+						></span
+					>
+					<span data-uix-switch
+						><input type="checkbox" bind:checked={showClear} /><span data-uix-switch-label
+							>Clear</span
+						></span
+					>
+					<span data-uix-switch
+						><input type="checkbox" bind:checked={showCancel} /><span data-uix-switch-label
+							>Cancel</span
+						></span
+					>
+					<span data-uix-switch
+						><input type="checkbox" bind:checked={showClose} /><span data-uix-switch-label
+							>Close</span
+						></span
+					>
+				</label>
 				<label data-uix-control>
 					<span data-uix-control-label>calendar behavior</span>
 					<span data-uix-switch><input type="checkbox" bind:checked={closeOnDateSelect} /><span data-uix-switch-label>close on select</span></span>
@@ -1009,6 +1027,16 @@
 	{/if}
 </div>
 
+{#snippet pickerFooter()}
+	{#if showFooter && (showClear || showCancel || showClose)}
+		<DatePicker.Footer>
+			{#if showClear}<DatePicker.Clear />{/if}
+			{#if showCancel}<DatePicker.Cancel />{/if}
+			{#if showClose}<DatePicker.Close />{/if}
+		</DatePicker.Footer>
+	{/if}
+{/snippet}
+
 {#snippet calendarBody({ months, weekdays, validationMessage }: DatePickerCalendarSnippetProps)}
 	<DatePicker.Header>
 		<DatePicker.PrevButton aria-label="Previous month">&lt;</DatePicker.PrevButton>

web/routes/uix/components/date-range-picker/+page.svelte

@@ -47,10 +47,8 @@
 	let stageRef = $state<HTMLElement | null>(null);
 	let value = $state<DateRange | undefined>({ start: sprintStart, end: sprintEnd });
 	let placeholder = $state<DateValue>(sprintStart);
-	// Popover starts open in the demo so the new Footer + segment-lock
-	// affordances are visible on first load. Consumers can close it via
-	// the Cancel/Close buttons or by clicking outside (in inline mode).
-	let open = $state(true);
+	// Popover starts closed. Consumers click the trigger icon to open.
+	let open = $state(false);
 	let startInput = $state(toDateInput(sprintStart));
 	let endInput = $state(toDateInput(sprintEnd));
 	let minInput = $state(toDateInput(defaultMin));
@@ -61,6 +59,14 @@
 	let closeOnRangeSelect = $state(false);
 	let mode = $state<'inline' | 'modal'>('inline');
 	let kind = $state<'date' | 'month' | 'year'>('date');
+
+	// Footer composition demo toggles. Visibility = whether the part is
+	// INCLUDED in the markup (the parts themselves render unconditionally).
+	let showFooter = $state(true);
+	let showClear = $state(true);
+	let showCancel = $state(true);
+	let showClose = $state(true);
+
 	let disableDaysOutsideMonth = $state(true);
 	let fixedWeeks = $state(true);
 	let pagedNavigation = $state(false);
@@ -714,6 +720,31 @@
 						{/each}
 					</span>
 				</label>
+				<label data-uix-control>
+					<span data-uix-control-label
+						>footer <span data-uix-control-hint>compose parts inside &lt;Footer&gt;</span></span
+					>
+					<span data-uix-switch
+						><input type="checkbox" bind:checked={showFooter} /><span data-uix-switch-label
+							>Footer</span
+						></span
+					>
+					<span data-uix-switch
+						><input type="checkbox" bind:checked={showClear} /><span data-uix-switch-label
+							>Clear</span
+						></span
+					>
+					<span data-uix-switch
+						><input type="checkbox" bind:checked={showCancel} /><span data-uix-switch-label
+							>Cancel</span
+						></span
+					>
+					<span data-uix-switch
+						><input type="checkbox" bind:checked={showClose} /><span data-uix-switch-label
+							>Close</span
+						></span
+					>
+				</label>
 				<label data-uix-control>
 					<span data-uix-control-label>states</span>
 					<span data-uix-switch><input type="checkbox" bind:checked={required} /><span data-uix-switch-label>required</span></span>
@@ -1051,11 +1082,17 @@
 			</div>
 		{/each}
 	</div>
-	<DateRangePicker.Footer>
-		<DateRangePicker.Clear />
-		<DateRangePicker.Cancel />
-		<DateRangePicker.Close />
-	</DateRangePicker.Footer>
+	{@render pickerFooter()}
+{/snippet}
+
+{#snippet pickerFooter()}
+	{#if showFooter && (showClear || showCancel || showClose)}
+		<DateRangePicker.Footer>
+			{#if showClear}<DateRangePicker.Clear />{/if}
+			{#if showCancel}<DateRangePicker.Cancel />{/if}
+			{#if showClose}<DateRangePicker.Close />{/if}
+		</DateRangePicker.Footer>
+	{/if}
 {/snippet}
 
 <style>