fix(coding-agent): harden project trust persistence

packages/coding-agent/test/trust-manager.test.ts

@@ -1,6 +1,7 @@
 import { mkdirSync, readFileSync, rmSync, writeFileSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
+import lockfile from "proper-lockfile";
 import { afterEach, beforeEach, describe, expect, it } from "vitest";
 import { hasProjectConfig, ProjectTrustStore } from "../src/core/trust-manager.ts";
 
@@ -43,6 +44,29 @@ describe("ProjectTrustStore", () => {
 		expect(readFileSync(trustPath, "utf-8")).toBe("{not json");
 	});
 
+	it("does not read trust.json while another process holds the trust lock", () => {
+		const trustPath = join(agentDir, "trust.json");
+		writeFileSync(trustPath, "{partial", "utf-8");
+		const release = lockfile.lockSync(agentDir, { realpath: false, lockfilePath: `${trustPath}.lock` });
+		const store = new ProjectTrustStore(agentDir);
+
+		try {
+			let error: unknown;
+			try {
+				store.get(cwd);
+			} catch (caught) {
+				error = caught;
+			}
+
+			expect(error).toBeInstanceOf(Error);
+			expect((error as { code?: unknown }).code).toBe("ELOCKED");
+		} finally {
+			release();
+		}
+
+		expect(() => store.get(cwd)).toThrow(/Failed to read trust store/);
+	});
+
 	it("detects .pi project config directories", () => {
 		expect(hasProjectConfig(cwd)).toBe(false);