refactor: remove runtime package installation from flash_windows

[abusaeed-shuvo]

Refactor: Remove runtime package installation from flash_windows

Target branch: dev
Labels: refactor, bug-fix

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Summary

Removed all runtime package installation logic from flash_windows.py. Tools like ntfs-3g, wimtools, and exfatprogs are now declared as system dependencies and expected to be present at runtime. Missing tools now raise a clean FileNotFoundError with a human-readable install hint instead of silently attempting installs.

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Changes

• _find_ntfs_tool() — removed apt/dnf/pacman/zypper install logic, removed unused status_cb parameter, now raises FileNotFoundError if no tool is found
• _ensure_wimlib() → renamed to _check_wimlib() — removed all install logic, now only checks for presence and raises on miss
• Added requirements-system.txt declaring: ntfs-3g, wimtools, exfatprogs, util-linux, udev, parted
• Removed unused contextlib import

No changes to requirements-python.txt — this file has no third-party Python dependencies.

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Before & After

Before (silent install attempt):

ntfs-3g not found, attempting to install...
[runs apt-get install -y ntfs-3g]

After (clean error):

FileNotFoundError: mkfs.ntfs / mkntfs not found. Install ntfs-3g:
sudo apt install ntfs-3g  /  sudo pacman -S ntfs-3g

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Known Limitations

• The download fallback for uefi-ntfs.img is still present — this is intentional and out of scope for this PR
• requirements-system.txt package names follow Debian/Arch conventions; names may differ on RPM-based distros (e.g. exfatprogs vs exfat-utils)

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AI Disclosure

This PR description was Generated by Copilot.

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Checklist

• PR is against dev branch
• No duplicate PRs
• AI use disclosed
• Known limitations stated
• PEP8 naming followed
• No GUI changes (no screenshots needed)

[R-Larocque]

Please ruff format your code.
Also, did you think of a way to implement some of these packages as native Python?

[abusaeed-shuvo]

Please ruff format your code. Also, did you think of a way to implement some of these packages as native Python?

Some packages can be replaced with their Python alternative library, but I don't have enough experience with them to implement them reliably.
Here is a list of packages that have Python alternatives for anyone interested in implementing them (I have used LLM for researching them):

LLM used: QWEN3.5 4B

tools:

• name: wimlib-imagex split
  purpose: "Split WIM/ESD files >4GiB for FAT32"
  python_library:
  available: true
  library: "pywimlib"
  notes: "Python bindings for wimlib"

• name: sfdisk
  purpose: "GPT partitioning"
  python_library:
  available: true
  library: "pyparted"
  notes: "Python bindings for libparted"

• name: partprobe
  purpose: "Notify kernel of partition changes"
  python_library:
  available: true
  library: "pyparted / pyudev"

• name: "blockdev --getsz"
  purpose: "Get disk size in sectors"
  python_library:
  available: true
  library: "stdlib / ioctl"
  notes: "Can use os.lseek() or ioctl() directly"

• name: udevadm settle
  purpose: "Wait for device events"
  python_library:
  available: true
  library: "pyudev"

• name: "wipefs -a"
  purpose: "Wipe partition signatures"
  python_library:
  available: true
  library: "raw os.open()/os.write()"
  notes: "Can be implemented directly in Python"

• name: mount / umount
  purpose: "Mount and unmount filesystems"
  python_library:
  available: false
  library: null
  notes: "No pure Python implementation; can use ctypes with mount(2)"

• name: dd
  purpose: "Write raw image to device"
  python_library:
  available: true
  library: "stdlib"
  notes: "Can use Python open() and write()"

• name: sync
  purpose: "Sync filesystem buffers"
  python_library:
  available: true
  library: "os.sync()"
  notes: "Available in Python standard library"

• name: which
  purpose: "Find executables"
  python_library:
  available: true
  library: "shutil.which()"
  notes: "Available in Python standard library"

• name: cp
  purpose: "Copy files"
  python_library:
  available: true
  library: "shutil"
  notes: "Already supported in Python"

• name: mkdir
  purpose: "Create directories"
  python_library:
  available: true
  library: "os.makedirs"
  notes: "Already supported in Python"

• name: mkfs.ntfs / mkntfs
  purpose: "Format NTFS"
  python_library:
  available: false
  library: null
  notes: "No reliable Python NTFS formatter"

• name: mkfs.exfat
  purpose: "Format exFAT"
  python_library:
  available: false
  library: null
  notes: "No Python exFAT formatter"

• name: "mkfs.vfat -F32"
  purpose: "Format FAT32"
  python_library:
  available: false
  library: null
  notes: "No Python FAT32 formatter"