fix(coding-agent/debug): Sanitized debug log rendering

- Sanitized debug log lines by stripping ANSI/control codes, replacing tabs, and truncating to terminal width.
- Added formatting helper and unit tests covering sanitization, tab handling, and truncation.

packages/coding-agent/test/debug/log-formatting.test.ts

@@ -0,0 +1,29 @@
+import { describe, expect, it } from "bun:test";
+import { formatDebugLogLine } from "../../src/debug/log-formatting";
+
+describe("formatDebugLogLine", () => {
+	it("strips ANSI codes and carriage returns", () => {
+		const input = "\u001b[31merror\r\u001b[0m";
+		const result = formatDebugLogLine(input, 80);
+		expect(result).toBe("error");
+	});
+
+	it("replaces tabs with spaces", () => {
+		const input = "col1\tcol2";
+		const result = formatDebugLogLine(input, 80);
+		expect(result).toBe("col1   col2");
+	});
+
+	it("removes unsafe control characters", () => {
+		const input = "ok\u0007bad";
+		const result = formatDebugLogLine(input, 80);
+		expect(result).toBe("okbad");
+	});
+
+	it("truncates long lines", () => {
+		const input = "0123456789ABCDEFGHIJ";
+		const result = formatDebugLogLine(input, 10);
+		expect(Bun.stringWidth(result)).toBeLessThanOrEqual(10);
+		expect(result.startsWith("012345")).toBe(true);
+	});
+});