fix: add CLI version flag

src/cli/main.ts

@@ -1,3 +1,4 @@
+import { createRequire } from "node:module";
 import { Command } from "commander";
 import { ClaudemuxError } from "../errors.js";
 import { type AskCliOpts, askCli } from "./ask.js";
@@ -16,6 +17,8 @@ import { stateCli } from "./state.js";
 import { turnCompleteCli } from "./turn-complete.js";
 import { type WaitCliOpts, waitCli } from "./wait.js";
 
+const packageJson = createRequire(import.meta.url)("../../package.json") as { version: string };
+
 /**
  * Build the `claudemux` commander entry. Exported separately from `bin/`
  * so tests can drive it without spawning a subprocess.
@@ -26,7 +29,10 @@ import { type WaitCliOpts, waitCli } from "./wait.js";
  */
 export function buildProgram(): Command {
   const program = new Command();
-  program.name("claudemux").description("Drive long-lived Claude Code sessions from Node.");
+  program
+    .name("claudemux")
+    .description("Drive long-lived Claude Code sessions from Node.")
+    .version(packageJson.version);
 
   // Every verb locates a session: namespace prefix + an explicit socket override
   // (the latter for dev / debugging — most users share the default socket).

test/cli/cli.test.ts

@@ -1,5 +1,5 @@
 import { spawn } from "node:child_process";
-import { existsSync } from "node:fs";
+import { existsSync, readFileSync } from "node:fs";
 import { dirname, join } from "node:path";
 import { fileURLToPath } from "node:url";
 import { afterEach, beforeEach, describe, expect, it } from "vitest";
@@ -14,6 +14,7 @@ import { Harness, claudeBinDir } from "../harness/index.js";
 const __dirname = dirname(fileURLToPath(import.meta.url));
 const repoRoot = join(__dirname, "..", "..");
 const binPath = join(repoRoot, "bin", "claudemux");
+const packageVersion = JSON.parse(readFileSync(join(repoRoot, "package.json"), "utf8")).version;
 
 // Real-claude boot is out of the hermetic gate (no `claude` in `npm test`/CI).
 // The block below spawns the installed-but-logged-OUT claude binary; run it
@@ -80,6 +81,13 @@ describe("CLI — bin/claudemux exists and is runnable", () => {
     }
   });
 
+  it("--version prints the package version", async () => {
+    const r = await runCli(["--version"]);
+    expect(r.exit).toBe(0);
+    expect(r.stdout.trim()).toBe(packageVersion);
+    expect(r.stderr).toBe("");
+  });
+
   it("--help output for every verb has ZERO references to 'tmux'", async () => {
     const verbs = [
       "spawn",