feat(settings): inline theme picker into Settings panel

The Theme button + ThemeSwitcher modal were a header-triggered modal.
That doesn't belong in a sidebar-panel architecture, and theme picking
is a UI preference that belongs alongside the other Settings entries.

- Add a "Theme" section as the first block in SettingsPanel with the
  same theme list as ThemeSwitcher.
- The localStorage key (`dispatch-theme`) and apply-on-change behavior
  are unchanged, so the boot-time theme apply in App.svelte's onMount
  keeps working without modification.
- Delete the now-unused ThemeSwitcher.svelte component; no remaining
  importers.

2 files changed, 52 insertions, 58 deletions

diff --git a/packages/frontend/src/lib/components/SettingsPanel.svelte b/packages/frontend/src/lib/components/SettingsPanel.svelte
index 392852a..efbaf5f 100644
--- a/packages/frontend/src/lib/components/SettingsPanel.svelte
+++ b/packages/frontend/src/lib/components/SettingsPanel.svelte
@@ -11,6 +11,42 @@ const {
 	apiBase?: string;
 } = $props();
 
+// Theme picker — was a header-triggered modal (`ThemeSwitcher.svelte`);
+// inlined here so theme picking lives in Settings alongside other UI
+// preferences. The list and localStorage key must stay in sync with the
+// boot-time theme apply in `App.svelte`'s `onMount`.
+const THEMES = [
+	"light",
+	"dark",
+	"dracula",
+	"night",
+	"nord",
+	"sunset",
+	"cyberpunk",
+	"forest",
+	"cmyk",
+	"coffee",
+	"caramellatte",
+	"garden",
+	"luxury",
+] as const;
+
+const THEME_STORAGE_KEY = "dispatch-theme";
+
+let currentTheme = $state(
+	(typeof localStorage !== "undefined" && localStorage.getItem(THEME_STORAGE_KEY)) || "dark",
+);
+
+function selectTheme(theme: string): void {
+	currentTheme = theme;
+	document.documentElement.setAttribute("data-theme", theme);
+	try {
+		localStorage.setItem(THEME_STORAGE_KEY, theme);
+	} catch {
+		// Best-effort — private mode / quota.
+	}
+}
+
 let titleKeyId = $state<string | null>(null);
 let titleModelId = $state<string | null>(null);
 let availableModels = $state<string[]>([]);
@@ -136,6 +172,22 @@ $effect(() => {
 	<div class="text-xs font-semibold text-base-content/50 uppercase tracking-wide">Settings</div>
 
 	<div class="flex flex-col gap-2">
+		<p class="text-xs text-base-content/70">Theme</p>
+		<label class="text-xs text-base-content/60">
+			Appearance
+			<select
+				class="select select-bordered select-sm w-full capitalize"
+				value={currentTheme}
+				onchange={(e) => selectTheme(e.currentTarget.value)}
+			>
+				{#each THEMES as theme (theme)}
+					<option value={theme} class="capitalize">{theme}</option>
+				{/each}
+			</select>
+		</label>
+
+		<div class="divider my-0"></div>
+
 		<p class="text-xs text-base-content/70">Title Generation Model</p>
 		<p class="text-xs text-base-content/40">Used to generate short titles for new tabs after the first message.</p>
 
diff --git a/packages/frontend/src/lib/components/ThemeSwitcher.svelte b/packages/frontend/src/lib/components/ThemeSwitcher.svelte
deleted file mode 100644
index 418fcea..0000000
--- a/packages/frontend/src/lib/components/ThemeSwitcher.svelte
+++ /dev/null
@@ -1,58 +0,0 @@
-<script lang="ts">
-const THEMES = [
-	"light",
-	"dark",
-	"dracula",
-	"night",
-	"nord",
-	"sunset",
-	"cyberpunk",
-	"forest",
-	"cmyk",
-	"coffee",
-	"caramellatte",
-	"garden",
-	"luxury",
-] as const;
-
-const STORAGE_KEY = "dispatch-theme";
-
-const { onclose }: { onclose: () => void } = $props();
-
-let currentTheme = $state(
-	(typeof localStorage !== "undefined" && localStorage.getItem(STORAGE_KEY)) || "dark",
-);
-
-let dialogEl: HTMLDialogElement | undefined = $state();
-
-$effect(() => {
-	if (dialogEl && !dialogEl.open) dialogEl.showModal();
-});
-
-function selectTheme(theme: string) {
-	currentTheme = theme;
-	document.documentElement.setAttribute("data-theme", theme);
-	localStorage.setItem(STORAGE_KEY, theme);
-	onclose();
-}
-</script>
-
-<dialog class="modal" bind:this={dialogEl} oncancel={onclose}>
-	<div class="modal-box w-56">
-		<h3 class="text-sm font-semibold mb-3">Select Theme</h3>
-		<ul class="menu menu-sm">
-			{#each THEMES as theme}
-				<li>
-					<button
-						type="button"
-						class="capitalize {currentTheme === theme ? 'menu-active' : ''}"
-						onclick={() => selectTheme(theme)}
-					>
-						{theme}
-					</button>
-				</li>
-			{/each}
-		</ul>
-	</div>
-	<form method="dialog" class="modal-backdrop"><button>close</button></form>
-</dialog>