refactor!: port shell scripts to Python package

Bash scripts were untestable and duplicated device/LUKS/mount logic;
the lim/ package centralizes it behind one subprocess wrapper and a
YAML image catalog (single point of truth).

BREAKING CHANGE: scripts/*.sh removed. Use `lim --type <cmd>`; new
types mount/umount/single-boot/raid1-boot/lock/unlock/import/export
replace direct script calls. --extra is deprecated and ignored.

- distributions.yml + lim/catalog.py hold the image catalog (PyYAML)
- pytest suite: 102 tests with mocked subprocess (tests/unit) and a
  250-line max file-length guard (tests/lint)
- ruff strict (select ALL), GitHub Actions CI, Dependabot; Travis gone
- Makefile: install (symlink ~/.local/bin/lim) and test targets
- fixes over bash: SUDO_USER-aware chown, mmcblk/nvme partition paths,
  sha512 checksum support, whole-pipeline failure detection, blkid
  UUID fallback for pre-mounted images, conditional fstab seeding for
  PARTUUID/LABEL images, clean errors for missing binaries

lim/image/setup.py

@@ -0,0 +1,96 @@
+"""Interactive Linux image setup: download, verify, transfer, configure.
+
+Reference for encrypted Raspberry Pi images:
+https://wiki.polaire.nl/doku.php?id=archlinux-raspberry-encrypted
+"""
+
+import pwd
+from pathlib import Path
+
+from lim import device as device_module
+from lim import system, ui
+from lim.errors import LimError
+from lim.image import choosers, transfer, verify
+from lim.image.plan import ImagePlan
+from lim.image.raspberry import configure_raspberry_image
+from lim.image.session import ImageSession
+
+
+def _prepare_image_folder(plan: ImagePlan) -> None:
+    ui.info("Configure user...")
+    origin_username = ui.ask("Please type in a valid working username:")
+    try:
+        pwd.getpwnam(origin_username)
+    except KeyError:
+        raise LimError(f"User {origin_username} doesn't exist.") from None
+
+    ui.info("Image routine starts...")
+    plan.image_folder = Path(f"/home/{origin_username}/Software/Images")
+    ui.info(f'The images will be stored in "{plan.image_folder}".')
+    if not plan.image_folder.is_dir():
+        ui.info(f'Folder "{plan.image_folder}" doesn\'t exist. It will be created now.')
+        plan.image_folder.mkdir(parents=True)
+
+
+def _select_unmounted_device() -> device_module.Device:
+    device = device_module.select_device()
+    if device_module.is_mounted(device.path):
+        raise LimError(
+            f'Device {device.path} is allready mounted. '
+            f'Umount with "umount {device.path}*".'
+        )
+    return device
+
+
+def _choose_and_verify_image(plan: ImagePlan) -> None:
+    plan.operation_system = ui.ask(
+        "Which operation system would you like to use [linux,windows,...]?"
+    )
+    if plan.operation_system == "linux":
+        choosers.choose_linux_image(plan)
+        plan.encrypt_system = ui.confirm("Should the system be encrypted?")
+        ui.info("Generating os-image...")
+        transfer.download_image(plan)
+    else:
+        choosers.choose_local_image(plan)
+
+    ui.info("Verifying image...")
+    ui.info("Verifying checksum...")
+    if plan.image_checksum is None and plan.download_url is not None:
+        plan.image_checksum = verify.resolve_checksum(plan.download_url)
+    verify.verify_checksum(plan.image_path, plan.image_checksum)
+    if plan.download_url is not None:
+        verify.verify_signature(plan.download_url, plan.image_path, plan.image_folder)
+
+
+def run_setup() -> None:
+    ui.info("Setupscript for images started...")
+    ui.info("Checking if root...")
+    if not system.is_root():
+        raise LimError("This script must be executed as root!")
+
+    plan = ImagePlan()
+    _prepare_image_folder(plan)
+    device = _select_unmounted_device()
+    _choose_and_verify_image(plan)
+
+    session = ImageSession(device)
+    try:
+        session.make_working_folder()
+        session.make_mount_folders()
+
+        plan.root_filesystem = ui.ask(
+            "Which filesystem should be used? E.g.:btrfs,ext4... (none):"
+        )
+
+        if ui.confirm(f"Should the image be transfered to {device.path}?"):
+            transfer.transfer_image(plan, session)
+        else:
+            ui.info("Skipping image transfer...")
+
+        if plan.raspberry_pi_version:
+            configure_raspberry_image(plan, session)
+    finally:
+        session.destructor()
+
+    ui.success("Setup successfull :)")