Converted CLI tests to use vitest (#1012)

* Pinned server-everything, fixed all tests to work with current pinned version, fixed problem with undetected failures (isError: true payloads).

* First working vitest implementation

* Refactoring some single-use configs fixtures and into the refeencing tests

* No tests refere to server-everything (or any other server from a registry), all tests actually validate what they say they test.

* Removed server-everything dep from CI, minor cleanup

* Addressed Claude PR review comments: Added tsx dev dependency, beefed up process termination (possible leak on Windows), beefed up http server cleanup (close all connections), removed unused hasValidJsonOutput, reduced CLI timeout to give it breathing room with vitest timeout.

* Made both stdio and http test servers fully composable, cleaned up types, terminology, and usage.

cli/__tests__/helpers/cli-runner.ts

@@ -0,0 +1,98 @@
+import { spawn } from "child_process";
+import { resolve } from "path";
+import { fileURLToPath } from "url";
+import { dirname } from "path";
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const CLI_PATH = resolve(__dirname, "../../build/cli.js");
+
+export interface CliResult {
+  exitCode: number | null;
+  stdout: string;
+  stderr: string;
+  output: string; // Combined stdout + stderr
+}
+
+export interface CliOptions {
+  timeout?: number;
+  cwd?: string;
+  env?: Record<string, string>;
+  signal?: AbortSignal;
+}
+
+/**
+ * Run the CLI with given arguments and capture output
+ */
+export async function runCli(
+  args: string[],
+  options: CliOptions = {},
+): Promise<CliResult> {
+  return new Promise((resolve, reject) => {
+    const child = spawn("node", [CLI_PATH, ...args], {
+      stdio: ["pipe", "pipe", "pipe"],
+      cwd: options.cwd,
+      env: { ...process.env, ...options.env },
+      signal: options.signal,
+      // Kill child process tree on exit
+      detached: false,
+    });
+
+    let stdout = "";
+    let stderr = "";
+    let resolved = false;
+
+    // Default timeout of 10 seconds (less than vitest's 15s)
+    const timeoutMs = options.timeout ?? 10000;
+    const timeout = setTimeout(() => {
+      if (!resolved) {
+        resolved = true;
+        // Kill the process and all its children
+        try {
+          if (process.platform === "win32") {
+            child.kill("SIGTERM");
+          } else {
+            // On Unix, kill the process group
+            process.kill(-child.pid!, "SIGTERM");
+          }
+        } catch (e) {
+          // Process might already be dead, try direct kill
+          try {
+            child.kill("SIGKILL");
+          } catch (e2) {
+            // Process is definitely dead
+          }
+        }
+        reject(new Error(`CLI command timed out after ${timeoutMs}ms`));
+      }
+    }, timeoutMs);
+
+    child.stdout.on("data", (data) => {
+      stdout += data.toString();
+    });
+
+    child.stderr.on("data", (data) => {
+      stderr += data.toString();
+    });
+
+    child.on("close", (code) => {
+      if (!resolved) {
+        resolved = true;
+        clearTimeout(timeout);
+        resolve({
+          exitCode: code,
+          stdout,
+          stderr,
+          output: stdout + stderr,
+        });
+      }
+    });
+
+    child.on("error", (error) => {
+      if (!resolved) {
+        resolved = true;
+        clearTimeout(timeout);
+        reject(error);
+      }
+    });
+  });
+}