fix(server): run cli.test.ts main() cases from an empty temp dir

packages/server/CLAUDE.md

@@ -108,6 +108,6 @@ for Cloudflare bindings.
   bindings (`secrets: { TOKEN_SIGNING_KEY, … }` in the `phase*` integration
   tests), and `env.test.ts` drives `loadDwkEnv({ cwd })` against temp dirs, so
   no secret file is needed locally or in CI. Add a new test's secrets inline
-  the same way. One leak: `cli.test.ts` calls `main()`, whose `loadDwkEnv()`
-  reads `.env`/`<domain>.env` from the working directory, so a local `.env`
-  there lands in `process.env` during that file.
+  the same way. `main()` calls `loadDwkEnv()` against `process.cwd()`, so
+  `cli.test.ts` runs every `main` case from an empty temp dir; keep new `main`
+  tests inside that `describe`.

packages/server/src/cli.test.ts

@@ -1,4 +1,4 @@
-import { describe, it, expect, afterAll } from "vitest";
+import { describe, it, expect, afterAll, beforeEach, afterEach } from "vitest";
 import { mkdtempSync, rmSync, writeFileSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
@@ -150,6 +150,17 @@ describe("dwk-serve CLI", () => {
   });
 
   describe("main", () => {
+    // main() calls loadDwkEnv() against process.cwd(); run every case from an
+    // empty temp dir so a developer's local .env never reaches these tests.
+    let prevCwd: string;
+    beforeEach(() => {
+      prevCwd = process.cwd();
+      process.chdir(workdir());
+    });
+    afterEach(() => {
+      process.chdir(prevCwd);
+    });
+
     it("parses args, loads the config path, and starts listening", async () => {
       const path = configFile(pingConfig());
       const cap = capture();