Upgrade @langchain/langgraph-sdk to 1.6.5 and @langchain/core to 1.1.31 (#230)

* Upgrade @langchain/langgraph-sdk from 0.1.9 to 1.6.5

Bumps the SDK to the latest stable release. Adds the required
`state_updated_at` field to the `emptyThread` test fixture to satisfy
the updated `Thread` type definition.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* Upgrade @langchain/core from 0.3.78 to 1.1.31

Resolves the peer dependency warning introduced when upgrading
@langchain/langgraph-sdk to 1.6.5, which requires @langchain/core ^1.1.16.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: dokterbob

apps/frontend/package.json

@@ -23,8 +23,8 @@
 		"@eslint/js": "^9.18.0",
 		"@inlang/paraglide-js": "^2.2.0",
 		"@internationalized/date": "^3.10.0",
-		"@langchain/core": "^0.3.78",
-		"@langchain/langgraph-sdk": "^0.1.9",
+		"@langchain/core": "^1.1.31",
+		"@langchain/langgraph-sdk": "^1.6.5",
 		"@lucide/svelte": "^0.562.0",
 		"@playwright/test": "^1.49.1",
 		"@sveltejs/adapter-node": "^5.2.12",

apps/frontend/src/lib/components/Chat.svelte.test.ts

@@ -30,6 +30,7 @@ const emptyThread: Thread<ThreadValues> = {
 	thread_id: 'test-123',
 	created_at: '2024-01-01',
 	updated_at: '2024-01-01',
+	state_updated_at: '2024-01-01',
 	metadata: {},
 	status: 'idle',
 	values: { messages: [] },