fix(terminal): drop native ARGV0 for bun-pty via env -u

bun-pty merges the OS environ into PTY children, so deleting ARGV0 from the
JS env object alone left the AppImage path in the shell. Wrap Linux PTY
spawns with env -u ARGV0, clear native ARGV0 under Bun via libc unsetenv,
and always clear process.env even when no login-shell snapshot exists.

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

packages/web/server/lib/inherited-env.test.js

@@ -1,5 +1,9 @@
 import { describe, expect, it } from 'vitest';
-import { stripAppImageArgv0Leak } from './inherited-env.js';
+import {
+  clearAppImageArgv0FromProcessEnv,
+  resolveLinuxPtyLaunch,
+  stripAppImageArgv0Leak,
+} from './inherited-env.js';
 
 describe('stripAppImageArgv0Leak', () => {
   it('removes ARGV0 from a child env object', () => {
@@ -27,3 +31,35 @@ describe('stripAppImageArgv0Leak', () => {
     expect(stripAppImageArgv0Leak(undefined)).toBeUndefined();
   });
 });
+
+describe('clearAppImageArgv0FromProcessEnv', () => {
+  it('removes ARGV0 from process.env', () => {
+    const previous = process.env.ARGV0;
+    process.env.ARGV0 = '/path/to/OpenChamber.AppImage';
+    try {
+      clearAppImageArgv0FromProcessEnv();
+      expect(process.env.ARGV0).toBeUndefined();
+    } finally {
+      if (previous === undefined) delete process.env.ARGV0;
+      else process.env.ARGV0 = previous;
+    }
+  });
+});
+
+describe('resolveLinuxPtyLaunch', () => {
+  it('wraps the shell with env -u ARGV0 on Linux', () => {
+    if (process.platform !== 'linux') return;
+    expect(resolveLinuxPtyLaunch('/bin/zsh', ['-l'])).toEqual({
+      executable: expect.stringMatching(/\/env$/),
+      args: ['-u', 'ARGV0', '/bin/zsh', '-l'],
+    });
+  });
+
+  it('leaves non-Linux launches unchanged', () => {
+    if (process.platform === 'linux') return;
+    expect(resolveLinuxPtyLaunch('/bin/zsh', ['-l'])).toEqual({
+      executable: '/bin/zsh',
+      args: ['-l'],
+    });
+  });
+});