macOS action's trailing workdir slash can break zsh prompts

[pgorczak]

Issue Description

Following up on #8932, the workingDirectory strings passed from openTerminal end with a slash. This can break the common zsh prompt sequence %1~ (final component of the working directory) which is then expanded to an empty string.

Here is a swift program that runs the path processing logic on the current clipboard contents. Copy a file or folder, and then run it with xcrun swift getUrl.swift. Note that the printed path always ends with a slash.

getUrl.swift

import AppKit
import Foundation

let pasteboard = NSPasteboard.general

guard
    let pathURLs = pasteboard.readObjects(
        forClasses: [NSURL.self], options: [.urlReadingFileURLsOnly: true]) as? [URL]
else {
    fatalError("no string")
}

let directoryURLs = Set(
    pathURLs.map { url -> URL in
        let isDirectory =
            (try? url.resourceValues(forKeys: [.isDirectoryKey]))?.isDirectory
            ?? url.hasDirectoryPath
        return isDirectory ? url : url.deletingLastPathComponent()
    }
)

guard !directoryURLs.isEmpty else {
    fatalError("no string")
}

for url in directoryURLs {
    let workingDirectory = url.path(percentEncoded: false)
    print(workingDirectory.debugDescription)
}

Expected Behavior

Set the working directory without the trailing slash so zsh understands it properly.

Actual Behavior

Zsh expands the prompt sequence %1~ (final component of the working directory) to an empty string due to the trailing slash.

Reproduction Steps

1. Launch Ghostty from the macOS action (new Ghostty Window here)
2. Observe the trailing slash in the title bar
3. See the %1~ prompt sequence expand to an empty string in zsh

Ghostty Logs

No response

Ghostty Version

Ghostty 1.3.1

Version
  - version: 1.3.1
  - channel: stable
Build Config
  - Zig version   : 0.15.2
  - build mode    : .ReleaseFast
  - app runtime   : .none
  - font engine   : .coretext
  - renderer      : renderer.generic.Renderer(renderer.Metal)
  - libxev        : kqueue

OS Version Information

MacOS 26.6.2

(Linux only) Display Server

None

(Linux only) Desktop Environment/Window Manager

No response

Minimal Ghostty Configuration

No config needed but do use zsh.

Additional Relevant Configuration

Behavior observed with zsh.

I acknowledge that:

• I have reviewed the FAQ and confirm that my issue is NOT among them.
• I have searched the Ghostty documentation and confirm there doesn't exist a configuration option that solves my issue.
• I have searched the Ghostty repository (both open and closed Discussions and Issues) and confirm this is not a duplicate of an existing issue or discussion.
• I have checked the "Preview" tab on all text fields to ensure that everything looks right, and have wrapped all configuration and code in code blocks with a group of three backticks (```) on separate lines.

[mitchellh]

Fixed #14051