feat(tabs): extract TabBar component with horizontal scroll + sticky end '+'

Move inline tab-bar markup from the composition root into a thin
presentational TabBar in the tabs feature (feature-as-a-library: pure
reducer -> reactive store -> UI). Adds overflow-x scroll (min-w-max strip)
and a sticky right-pinned new-chat '+' that floats over scrolling tabs.
Draft-on-select / create-on-send behavior unchanged.

1 files changed, 54 insertions, 0 deletions

diff --git a/src/features/tabs/ui/TabBar.svelte b/src/features/tabs/ui/TabBar.svelte
new file mode 100644
index 0000000..76fab05
--- /dev/null
+++ b/src/features/tabs/ui/TabBar.svelte
@@ -0,0 +1,54 @@
+<script lang="ts">
+	import type { Tab } from "../tabs";
+
+	let {
+		tabs,
+		activeConversationId,
+		onSelect,
+		onClose,
+		onNewDraft,
+	}: {
+		tabs: readonly Tab[];
+		activeConversationId: string | null;
+		onSelect: (conversationId: string) => void;
+		onClose: (conversationId: string) => void;
+		onNewDraft: () => void;
+	} = $props();
+</script>
+
+<div class="overflow-x-auto border-b border-base-300">
+	<div class="tabs tabs-border min-w-max">
+		{#each tabs as tab (tab.conversationId)}
+			<div
+				class="tab"
+				class:tab-active={tab.conversationId === activeConversationId}
+				role="tab"
+				tabindex="0"
+				onclick={() => onSelect(tab.conversationId)}
+				onkeydown={(e) => {
+					if (e.key === "Enter") onSelect(tab.conversationId);
+				}}
+			>
+				<span class="max-w-[120px] truncate">{tab.title}</span>
+				<button
+					class="btn btn-ghost btn-xs ml-1"
+					aria-label="Close tab"
+					onclick={(e) => {
+						e.stopPropagation();
+						onClose(tab.conversationId);
+					}}
+				>
+					&times;
+				</button>
+			</div>
+		{/each}
+		<button
+			class="tab sticky right-0 z-10 bg-base-200 shadow-[-2px_0_4px_-1px_rgba(0,0,0,0.2)]"
+			class:tab-active={activeConversationId === null}
+			aria-label="New chat"
+			onclick={() => onNewDraft()}
+		>
+			+
+		</button>
+	</div>
+</div>