Add Claude Rust SDK integration with feature flag

Add experimental support for using the Rust SDK (claude-agent-sdk-rs)
instead of spawning the Claude binary. The SDK implementation handles
session management, MCP server configuration, system prompts, streaming
responses, and user cancellation. A toggle in project Agent Settings
controls which backend is used.
save 3

Author: mtsgrd

Cargo.lock

@@ -14,6 +14,7 @@
 	let dangerouslyAllowAllPermissions = $state(false);
 	let autoCommitAfterCompletion = $state(true);
 	let useConfiguredModel = $state(false);
+	let useRustSdk = $state(false);
 
 	// Initialize Claude settings from store
 	$effect(() => {
@@ -23,6 +24,7 @@
 			dangerouslyAllowAllPermissions = $settingsStore.claude.dangerouslyAllowAllPermissions;
 			autoCommitAfterCompletion = $settingsStore.claude.autoCommitAfterCompletion;
 			useConfiguredModel = $settingsStore.claude.useConfiguredModel;
+			useRustSdk = $settingsStore.claude.useRustSdk;
 		}
 	});
 
@@ -50,6 +52,11 @@
 		useConfiguredModel = value;
 		await settingsService.updateClaude({ useConfiguredModel: value });
 	}
+
+	async function updateUseRustSdk(value: boolean) {
+		useRustSdk = value;
+		await settingsService.updateClaude({ useRustSdk: value });
+	}
 </script>
 
 <CardGroup.Item standalone>
@@ -98,6 +105,18 @@
 	{/snippet}
 </CardGroup.Item>
 
+<CardGroup.Item standalone labelFor="useRustSdk">
+	{#snippet title()}
+		Use Claude Rust SDK
+	{/snippet}
+	{#snippet caption()}
+		Use the Rust SDK instead of spawning the Claude binary. (Experimental)
+	{/snippet}
+	{#snippet actions()}
+		<Toggle id="useRustSdk" checked={useRustSdk} onchange={updateUseRustSdk} />
+	{/snippet}
+</CardGroup.Item>
+
 <CardGroup.Item standalone labelFor="newlineOnEnter">
 	{#snippet title()}
 		Newline on Enter

apps/desktop/src/components/projectSettings/AgentSettings.svelte

@@ -43,3 +43,5 @@ tracing.workspace = true
 nix = { version = "0.30.1", features = ["signal"] }
 notify-rust = { workspace = true }
 url.workspace = true
+futures.workspace = true
+claude-agent-sdk-rs = "0.6"