v0.14.1: Windows setup and dependency recovery

v0.14.1: Windows setup and dependency recovery

Windows startup previously stopped when FFmpeg or ffprobe was unavailable, while
install.cmd only set up Python packages. This patch adds a Windows setup
assistant and recovery choices to make a fresh installation usable.

• Add setup-windows.cmd and .ps1. Check Python 3.10+, venv, ensurepip, pip,
  pinned Python dependencies, FFmpeg and ffprobe. Offer exact-ID WinGet installs
  of missing Python or Gyan.FFmpeg from the winget source.
• Route install.cmd and run.cmd --setup through the assistant before Python
  is required. Keep working installations and preserve existing configuration.
• Offer setup at Windows GUI startup when dependencies are missing. Recheck
  after success, then continue with the original arguments and caller directory.
  Declining, failing or incomplete setup stops startup without retry loops.
• Refresh the process PATH while retaining session entries. Discover FFmpeg in
  WinGet and local portable directories, or beside a configured companion tool.
• Add explicit Python/FFmpeg path selection, INI backups, read-only -Check,
  and optional Git/analysis installation. Keep 64tass and VICE optional for
  ordinary GUI/audio/PRG use; CRT export still requires VICE's cartconv.
• Improve missing-tool guidance and check pip in the read-only doctor.
• Surround the startup instructions with terminal-width hyphen lines and bold
  the three keep-open/shutdown instructions on supported terminals. Redirected
  output remains plain, with no additional Python dependencies.
• Print clear GUI startup instructions: the service is running and accessible only
  on this computer, open the displayed URL if the browser did not launch, and
  keep the terminal open. Press Ctrl+C to stop the service and exit; closing
  the browser tab alone does not stop it.
• Bump the shared version to 0.14.1. CLI, GUI and generated reports read VERSION.

Apply and run

Extract the incremental ZIP from the parent of audio-bitsqueezer, then run
these commands from the project directory on Windows:

.\setup-windows.cmd
.\run.cmd gui

The v0.14.1 incremental ZIP includes the full Windows setup change and can be
applied directly over the supplied v0.14.0 workspace or the earlier setup r1 patch.
See Windows setup and recovery for options and manual sources.

Validation

The implementation's full Python suite passed 92 tests with 8 skipped. Final
focused verification passed 21 setup/recovery tests (2 Windows-only skips) and
all 18 launcher integration tests. All three PowerShell scripts passed grammar
parsing. The patch-version update was checked across the modern command-line
entry points, GUI's shared version, release notes and archive manifests.

The GUI startup message was checked with the local server: the URL remained
usable when browser opening returned False, and Ctrl+C stopped the server cleanly.

Native Windows PowerShell execution, real WinGet installation and Windows GUI
continuation still require a native Windows run. The skipped optional audit/VICE
checks and native Windows checks are recorded in CHECKPOINT.md. Original legacy
sources and bundled C64 assets remain unchanged. No GitHub publication was
performed while preparing this update.