feat(lists+tasks): inline add-form at end of list, suggestions below input

UX change per direct user request:

  - Add-item / add-task form no longer sticks to the bottom of the viewport.
    It's now the last element of the unchecked/pending section, sitting
    just above the Checked/Completed section (option `a` of the review).
  - On /lists/[id] the frequency suggestion chips moved from ABOVE the
    input to BELOW it, forming a two-line block (input row on top, chips
    on the second line). Chips keep their responsive behavior — horizontal
    scroll on mobile, wrap on desktop (ItemSuggestions already handles
    that).
  - Empty-state message still shows when the list has no items; the form
    renders below it so you can add the first item without scrolling.
  - The form disappears while selection mode is active on /lists/[id]
    (selection chrome takes over the bottom).

Implementation
  /lists/[id]/+page.svelte
    - Removed the `absolute bottom-0` sticky form block.
    - New `addItemForm` Svelte snippet rendered at the end of unchecked
      items AND in the empty-state branch, gated by `!selectionMode`.
    - ItemSuggestions moved inside the snippet, below the input.
    - pb-32 scroll padding reduced to pb-16/md:pb-6 (no more sticky
      overlapping the last row).
  /tasks/[id]/+page.svelte
    - Same treatment with an `addTaskForm` snippet (no suggestions).

Tests
  All existing D- / T-UI- / selection tests pass unchanged: the locators
  are placeholder-based and the form is still findable regardless of
  placement. `data-testid="add-item-form"` / `"add-task-form"` added as
  future-proof hooks.

Verification
  just test-all → exit 0, 233 green, 2 skipped.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/web/src/routes/(app)/lists/[id]/+page.svelte

@@ -670,7 +670,7 @@
 		<SyncBanner />
 
 		<!-- Items -->
-		<div class="flex-1 overflow-y-auto pb-32">
+		<div class="flex-1 overflow-y-auto pb-16 md:pb-6">
 			<!-- Inline rename title — matches /notes editor pattern. Autosaves after
 			     NAME_SAVE_DEBOUNCE_MS of inactivity. -->
 			<div class="px-4 pt-4 pb-2 md:px-8 md:pt-6 md:pb-4">
@@ -692,6 +692,7 @@
 					<p class="mb-1 text-sm font-medium text-text-primary">{m.list_items_empty()}</p>
 					<p class="text-sm text-text-muted">{m.list_items_empty_hint()}</p>
 				</div>
+				{@render addItemForm()}
 			{:else}
 				<!-- Unchecked items (drag & droppable via left handle) -->
 				{#if uncheckedItems.length > 0}
@@ -823,6 +824,10 @@
 					</div>
 				{/if}
 
+				<!-- Inline add-item form. Always rendered between unchecked and checked
+				     sections (option `a` from the UX review); hidden in selection mode. -->
+				{@render addItemForm()}
+
 				<!-- Checked items section — separate zone, symmetric swipe-to-uncheck -->
 				{#if checkedItems.length > 0}
 					<div class="px-4 md:px-8 mt-4">
@@ -945,29 +950,22 @@
 			</div>
 		{/if}
 
-		<!-- Sticky bottom: suggestions + add form (hidden during selection). -->
-		<div
-			class="absolute inset-x-0 bottom-0 bg-background/80 backdrop-blur-[12px] mb-16 md:left-56 md:right-0 md:mb-0 {selectionMode ? 'hidden' : ''}"
-		>
-			<!-- Suggestions -->
-			<ItemSuggestions
-				{suggestions}
-				activePrefix={newName}
-				onselect={selectSuggestion}
-			/>
+	</div>
 
-			<!-- Add input -->
-			<div class="flex items-center gap-2 px-4 pb-4 pt-1">
-				<div class="flex flex-1 items-center gap-2 rounded-lg bg-surface px-4 py-2.5
-					shadow-[0px_2px_8px_rgba(15,23,42,0.06)]">
+	<!-- Inline add-item form: input row on top, frequency chips below.
+	     Hidden in selection mode per UX decision 6. -->
+	{#snippet addItemForm()}
+		{#if !selectionMode}
+			<div class="px-4 pt-2 pb-6 md:px-8" data-testid="add-item-form">
+				<div class="flex items-center gap-2">
+					<div class="flex flex-1 items-center gap-2 rounded-lg bg-surface px-4 py-2.5 shadow-[0px_2px_8px_rgba(15,23,42,0.06)]">
 						<input
 							bind:this={nameInput}
 							bind:value={newName}
 							onkeydown={handleAddKeydown}
 							type="text"
 							placeholder={m.list_item_placeholder()}
-						class="min-w-0 flex-1 bg-transparent text-sm text-text-primary placeholder:text-text-muted
-							outline-none"
+							class="min-w-0 flex-1 bg-transparent text-sm text-text-primary placeholder:text-text-muted outline-none"
 						/>
 						<input
 							bind:value={newQty}
@@ -975,23 +973,27 @@
 							min="1"
 							placeholder={m.list_qty_label()}
 							onkeydown={handleAddKeydown}
-						class="w-12 bg-transparent text-sm text-text-secondary placeholder:text-text-muted
-							outline-none text-right"
+							class="w-12 bg-transparent text-sm text-text-secondary placeholder:text-text-muted outline-none text-right"
 						/>
 					</div>
 					<button
 						onclick={handleAdd}
 						disabled={!newName.trim()}
-					class="flex h-10 w-10 shrink-0 items-center justify-center rounded-lg
-						bg-slate-900 text-white hover:opacity-90 disabled:opacity-40
-						dark:bg-white dark:text-slate-900 transition-opacity"
+						class="flex h-10 w-10 shrink-0 items-center justify-center rounded-lg bg-slate-900 text-white hover:opacity-90 disabled:opacity-40 dark:bg-white dark:text-slate-900 transition-opacity"
 						aria-label={m.add()}
 					>
 						<Plus size={18} strokeWidth={2} />
 					</button>
 				</div>
+				<!-- Suggestions — second line, right below the input. -->
+				<ItemSuggestions
+					{suggestions}
+					activePrefix={newName}
+					onselect={selectSuggestion}
+				/>
 			</div>
-	</div>
+		{/if}
+	{/snippet}
 
 	<!-- Double-tap edit overlay -->
 	{#if overlayItem}

apps/web/src/routes/(app)/tasks/[id]/+page.svelte

@@ -254,6 +254,7 @@
 				<p class="text-sm font-medium text-text-primary">{m.tasks_empty()}</p>
 				<p class="mt-1 text-sm text-text-secondary">{m.tasks_empty_hint()}</p>
 			</div>
+			{@render addTaskForm()}
 		{:else}
 			<!-- Pending (drag-and-drop reorderable) -->
 			{#if pendingTasks.length > 0}
@@ -312,6 +313,9 @@
 				</section>
 			{/if}
 
+			<!-- Inline add-task form between pending and completed (option `a`). -->
+			{@render addTaskForm()}
+
 			<!-- Completed (sunk to bottom; not reorderable) -->
 			{#if completedTasks.length > 0}
 				<section class="mt-6">
@@ -358,8 +362,11 @@
 		{/if}
 	</div>
 
-	<!-- Sticky add-task input -->
-	<div class="border-t border-black/5 bg-surface-raised px-4 py-3 md:px-6 md:py-4 dark:border-white/5">
+	</div>
+
+	<!-- Inline add-task form: input row on top, no suggestions for tasks. -->
+	{#snippet addTaskForm()}
+		<div class="mt-3 pb-6" data-testid="add-task-form">
 			<div class="flex items-center gap-2">
 				<div class="flex flex-1 items-center gap-2 rounded-lg bg-surface px-3 py-2 shadow-[0px_2px_8px_rgba(15,23,42,0.06)]">
 					<input
@@ -381,4 +388,4 @@
 				</button>
 			</div>
 		</div>
-</div>
+	{/snippet}