refactor(coding-agent): reorganized test files to proper test directory structure

- Moved test files from src/core to test/core directory.
- Moved test files from src/core/tools to test/tools directory.
- Moved test files from src/discovery to test/discovery directory.
- Updated import paths to reflect new test file locations.

packages/coding-agent/test/core/python-kernel-display.test.ts

@@ -0,0 +1,54 @@
+import { describe, expect, it } from "bun:test";
+import { type KernelDisplayOutput, PythonKernel } from "../../src/core/python-kernel";
+
+const renderDisplay = (
+	PythonKernel as unknown as {
+		prototype: {
+			renderDisplay: (content: Record<string, unknown>) => {
+				text: string;
+				outputs: KernelDisplayOutput[];
+			};
+		};
+	}
+).prototype.renderDisplay;
+
+describe("PythonKernel display rendering", () => {
+	it("normalizes text/plain output and returns no display outputs", () => {
+		const { text, outputs } = renderDisplay.call({} as PythonKernel, {
+			data: { "text/plain": "hello" },
+		});
+
+		expect(text).toBe("hello\n");
+		expect(outputs).toHaveLength(0);
+	});
+
+	it("collects image and json display outputs without text", () => {
+		const { text, outputs } = renderDisplay.call({} as PythonKernel, {
+			data: { "image/png": "abc", "application/json": { foo: "bar" } },
+		});
+
+		expect(text).toBe("");
+		expect(outputs).toEqual([
+			{ type: "image", data: "abc", mimeType: "image/png" },
+			{ type: "json", data: { foo: "bar" } },
+		]);
+	});
+
+	it("converts text/html to markdown", () => {
+		const { text, outputs } = renderDisplay.call({} as PythonKernel, {
+			data: { "text/html": "<p><strong>Hello</strong></p>" },
+		});
+
+		expect(outputs).toHaveLength(0);
+		expect(text).toBe("**Hello**\n");
+	});
+
+	it("combines text/plain with json output", () => {
+		const { text, outputs } = renderDisplay.call({} as PythonKernel, {
+			data: { "text/plain": "value", "application/json": { ok: true } },
+		});
+
+		expect(text).toBe("value\n");
+		expect(outputs).toEqual([{ type: "json", data: { ok: true } }]);
+	});
+});