Fix timeout issue in custom-system-prompt test

- Increase timeout from 5000ms to 10000ms for Windows compatibility
- Test was timing out on Windows due to slower file system operations

Author: StevenTCramer

src/core/prompts/__tests__/custom-system-prompt.spec.ts

@@ -96,7 +96,7 @@ describe("File-Based Custom System Prompt", () => {
 		expect(prompt).toContain("CAPABILITIES")
 		expect(prompt).toContain("MODES")
 		expect(prompt).toContain("Test role definition")
-	})
+	}, 10000)
 
 	it("should use file-based custom system prompt when available", async () => {
 		// Mock the readFile to return content from a file