sync: bug fixes + eval system from private repo

- Fix chunk_status: pass chunk_status/chunk/metadata to context builder
- Fix vector search: scope by node_id BEFORE similarity search
- Add eval logging system (RAH_EVALS_LOG=1)
- Add eval dashboard at /evals
- Add vitest for testing

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tests/evals/scenarios/create-node.ts

@@ -0,0 +1,15 @@
+import { Scenario } from '../types';
+
+export const scenario: Scenario = {
+  id: 'create-node',
+  name: 'Create node request',
+  description: 'Create a new node via chat.',
+  tools: ['createNode'],
+  input: {
+    message: 'Create a node titled "Eval: Test Node" with a short summary about evals.',
+  },
+  expect: {
+    toolsCalledSoft: ['createNode'],
+    responseContainsSoft: ['node', 'created', 'added'],
+  },
+};