feat: system prompt editor, tool permissions save-on-send, responsive sidebar, UI polish

- System Prompt sidebar view: editable textarea, save-on-send, reset button
- Tool permissions: save-on-send pattern (not immediate), reset button
- Dynamic system prompt: buildSystemPrompt reads from DB, tool list auto-generated
- Responsive sidebar: overlay on small screens with backdrop
- Chat bubbles: user=fit-width, assistant=full-width
- Fix  infinite loops (use onMount for data fetching)
- Fix sendMessage race condition (await settings saves before chat POST)
- Model selector: auto-open model modal after key selection
- Rename views: Permissions->Tools, Tab Settings->Model Choice
- Shared appSettings store for cross-component reactive state
- Delete old chat.svelte.ts

5 files changed, 103 insertions, 31 deletions

diff --git a/packages/frontend/src/lib/components/ChatMessage.svelte b/packages/frontend/src/lib/components/ChatMessage.svelte
index 4db57c3..398bee8 100644
--- a/packages/frontend/src/lib/components/ChatMessage.svelte
+++ b/packages/frontend/src/lib/components/ChatMessage.svelte
@@ -21,8 +21,8 @@ const isSystem = $derived(message.role === "system");
 		</div>
 	</div>
 {:else}
-<div class="chat chat-start mb-2">
-	<div class="chat-bubble max-w-[80%] break-words {isUser ? 'chat-bubble-primary' : 'bg-transparent'}">
+<div class="chat chat-start mb-2 [&>.chat-bubble]:max-w-full">
+	<div class="chat-bubble break-words {isUser ? 'chat-bubble-primary w-fit' : 'bg-transparent w-full'}">
 		{#if message.thinking}
 			<div class="collapse collapse-arrow mb-2 p-1">
 				<input type="checkbox" checked={appSettings.autoExpandThinking} />
diff --git a/packages/frontend/src/lib/components/ModelSelector.svelte b/packages/frontend/src/lib/components/ModelSelector.svelte
index b88b2e3..0af5ae6 100644
--- a/packages/frontend/src/lib/components/ModelSelector.svelte
+++ b/packages/frontend/src/lib/components/ModelSelector.svelte
@@ -44,16 +44,19 @@
 	function selectKey(keyId: string) {
 		showKeyModal = false;
 		onKeyChange(keyId);
+		// Immediately open model selection for the new key
+		openModelModal(keyId);
 	}
 
-	async function openModelModal() {
-		if (!activeKeyId) return;
+	async function openModelModal(keyIdOverride?: string) {
+		const keyId = keyIdOverride ?? activeKeyId;
+		if (!keyId) return;
 		showModelModal = true;
 		modelError = null;
 
 		// Check session cache
-		if (modelCache.has(activeKeyId)) {
-			availableModels = modelCache.get(activeKeyId)!;
+		if (modelCache.has(keyId)) {
+			availableModels = modelCache.get(keyId)!;
 			loadingModels = false;
 			return;
 		}
@@ -63,7 +66,7 @@
 
 		try {
 			const res = await fetch(
-				`${config.apiBase}/models/available?keyId=${encodeURIComponent(activeKeyId)}`,
+				`${config.apiBase}/models/available?keyId=${encodeURIComponent(keyId)}`,
 			);
 			if (!res.ok) {
 				const data = await res.json().catch(() => ({}));
@@ -73,7 +76,7 @@
 			const data = await res.json();
 			availableModels = data.models ?? [];
 			// Cache for session
-			modelCache.set(activeKeyId, availableModels);
+			modelCache.set(keyId, availableModels);
 		} catch (err) {
 			modelError = err instanceof Error ? err.message : "Failed to fetch models";
 		} finally {
@@ -99,7 +102,7 @@
 
 	<div class="flex items-center justify-between mt-2">
 		<span class="text-sm font-medium">Model</span>
-		<button class="btn btn-sm btn-outline" onclick={openModelModal} disabled={!activeKeyId}>
+		<button class="btn btn-sm btn-outline" onclick={() => openModelModal()} disabled={!activeKeyId}>
 			{activeModelId ?? "Select Model"}
 		</button>
 	</div>
diff --git a/packages/frontend/src/lib/components/PermissionLog.svelte b/packages/frontend/src/lib/components/PermissionLog.svelte
index 06607de..7733dcf 100644
--- a/packages/frontend/src/lib/components/PermissionLog.svelte
+++ b/packages/frontend/src/lib/components/PermissionLog.svelte
@@ -1,5 +1,7 @@
 <script lang="ts">
+import { onMount } from "svelte";
 import type { LogEntry } from "../types.js";
+import { appSettings } from "../settings.svelte.js";
 
 const { entries, apiBase = "" }: { entries: LogEntry[]; apiBase?: string } = $props();
 
@@ -16,46 +18,41 @@ const toolPermissions: ToolPermission[] = [
 	{ id: "external_directory", label: "External directories", description: "Allow access to files outside the workspace" },
 ];
 
-let permStates = $state<Record<string, boolean>>({
-	read: true,
-	edit: false,
-	bash: false,
-	external_directory: false,
-});
-
 async function loadPermissions(): Promise<void> {
+	const loaded: Record<string, boolean> = { ...appSettings.toolPerms };
 	for (const perm of toolPermissions) {
 		try {
 			const res = await fetch(`${apiBase}/tabs/settings/perm_${perm.id}`);
 			if (res.ok) {
 				const data = await res.json() as { value: string | null };
 				if (data.value !== null) {
-					permStates[perm.id] = data.value === "allow";
+					loaded[perm.id] = data.value === "allow";
 				}
 			}
 		} catch {
 			// ignore
 		}
 	}
+	appSettings.toolPerms = { ...loaded };
+	appSettings.savedToolPerms = { ...loaded };
 }
 
-async function togglePermission(id: string): Promise<void> {
-	permStates[id] = !permStates[id];
-	const value = permStates[id] ? "allow" : "ask";
-	fetch(`${apiBase}/tabs/settings/perm_${id}`, {
-		method: "PUT",
-		headers: { "Content-Type": "application/json" },
-		body: JSON.stringify({ value }),
-	}).catch(() => {});
+function togglePermission(id: string): void {
+	appSettings.toolPerms = { ...appSettings.toolPerms, [id]: !appSettings.toolPerms[id] };
 }
 
-$effect(() => {
-	void loadPermissions();
+function resetPermissions(): void {
+	appSettings.toolPerms = { ...appSettings.savedToolPerms };
+}
+
+onMount(() => {
+	loadPermissions();
 });
 </script>
 
 <div class="flex flex-col gap-3">
 	<div class="text-xs font-semibold text-base-content/50 uppercase tracking-wide">Tool Permissions</div>
+	<p class="text-xs text-base-content/40">Changes are applied when you send your next message.</p>
 
 	<div class="flex flex-col gap-1.5">
 		{#each toolPermissions as perm (perm.id)}
@@ -63,7 +60,7 @@ $effect(() => {
 				<input
 					type="checkbox"
 					class="checkbox checkbox-sm rounded-sm mt-0.5"
-					checked={permStates[perm.id]}
+					checked={appSettings.toolPerms[perm.id]}
 					onchange={() => togglePermission(perm.id)}
 				/>
 				<div class="flex flex-col">
@@ -74,6 +71,14 @@ $effect(() => {
 		{/each}
 	</div>
 
+	<button
+		class="btn btn-sm btn-ghost w-full"
+		disabled={!appSettings.toolPermsDirty}
+		onclick={resetPermissions}
+	>
+		Reset
+	</button>
+
 	<p class="text-xs text-base-content/40">Warning: changing tool access will reset the AI's prompt cache for active conversations, which may increase usage costs.</p>
 
 	<!-- Permission Log -->
diff --git a/packages/frontend/src/lib/components/SidebarPanel.svelte b/packages/frontend/src/lib/components/SidebarPanel.svelte
index 9aca408..93d528e 100644
--- a/packages/frontend/src/lib/components/SidebarPanel.svelte
+++ b/packages/frontend/src/lib/components/SidebarPanel.svelte
@@ -8,6 +8,7 @@
 	import KeyUsage from "./KeyUsage.svelte";
 	import ClaudeReset from "./ClaudeReset.svelte";
 	import SettingsPanel from "./SettingsPanel.svelte";
+	import SystemPromptPanel from "./SystemPromptPanel.svelte";
 	import type { TaskItem, LogEntry, KeyInfo } from "../types.js";
 
 	const {
@@ -42,7 +43,7 @@
 	let nextId = 0;
 	let panels = $state<Panel[]>([{ id: nextId++, selected: "Model Choice" }]);
 
-	const viewOptions = ["Select a view", "Model Choice", "Key Usage", "Claude Reset", "Model Status", "Tasks", "Config", "Skills", "Permissions", "Settings"];
+	const viewOptions = ["Select a view", "Model Choice", "Key Usage", "Claude Reset", "Model Status", "Tasks", "Config", "Skills", "Tools", "System Prompt", "Settings"];
 
 	function addPanel() {
 		panels = [...panels, { id: nextId++, selected: "Select a view" }];
@@ -113,9 +114,11 @@
 					<ConfigPanel {apiBase} />
 				{:else if panel.selected === "Skills"}
 					<SkillsBrowser {apiBase} />
-				{:else if panel.selected === "Permissions"}
+				{:else if panel.selected === "Tools"}
 					<PermissionLog entries={permissionLog} {apiBase} />
-				{:else if panel.selected === "Settings"}
+				{:else if panel.selected === "System Prompt"}
+				<SystemPromptPanel {apiBase} />
+			{:else if panel.selected === "Settings"}
 					<SettingsPanel {keys} {apiBase} />
 				{/if}
 			</div>
diff --git a/packages/frontend/src/lib/components/SystemPromptPanel.svelte b/packages/frontend/src/lib/components/SystemPromptPanel.svelte
new file mode 100644
index 0000000..6b91ebe
--- /dev/null
+++ b/packages/frontend/src/lib/components/SystemPromptPanel.svelte
@@ -0,0 +1,61 @@
+<script lang="ts">
+	import { onMount } from "svelte";
+	import { appSettings } from "../settings.svelte.js";
+
+	const {
+		apiBase = "",
+	}: {
+		apiBase?: string;
+	} = $props();
+
+	const DEFAULT_PROMPT = "You are Dispatch, a helpful AI coding assistant. Be concise and helpful.";
+
+	async function loadPrompt(): Promise<void> {
+		try {
+			const res = await fetch(`${apiBase}/tabs/settings/system_prompt`);
+			if (res.ok) {
+				const data = await res.json() as { value: string | null };
+				const value = data.value ?? DEFAULT_PROMPT;
+				appSettings.systemPrompt = value;
+				appSettings.savedSystemPrompt = value;
+			}
+		} catch {
+			// ignore
+		}
+	}
+
+	function resetPrompt(): void {
+		appSettings.systemPrompt = appSettings.savedSystemPrompt;
+	}
+
+	const isDirty = $derived(appSettings.systemPrompt !== appSettings.savedSystemPrompt);
+
+	onMount(() => {
+		if (!appSettings.systemPrompt) {
+			appSettings.systemPrompt = DEFAULT_PROMPT;
+			appSettings.savedSystemPrompt = DEFAULT_PROMPT;
+		}
+		loadPrompt();
+	});
+</script>
+
+<div class="flex flex-col gap-3 flex-1 min-h-0">
+	<div class="text-xs font-semibold text-base-content/50 uppercase tracking-wide">System Prompt</div>
+	<p class="text-xs text-base-content/40">The base instructions sent to the AI at the start of every conversation. Tool descriptions are appended automatically. Changes are applied when you send your next message.</p>
+
+	<textarea
+		class="textarea textarea-bordered w-full flex-1 min-h-32 text-xs font-mono leading-relaxed"
+		bind:value={appSettings.systemPrompt}
+		placeholder="Enter system prompt..."
+	></textarea>
+
+	<button
+		class="btn btn-sm btn-ghost w-full"
+		disabled={!isDirty}
+		onclick={resetPrompt}
+	>
+		Reset
+	</button>
+
+	<p class="text-xs text-base-content/40">Warning: changing the system prompt will reset the AI's prompt cache for active conversations, which may increase usage costs.</p>
+</div>