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/storage/common.py

@@ -0,0 +1,38 @@
+"""Shared path derivation for encrypted storage setups."""
+
+from dataclasses import dataclass
+
+from lim import device as device_module
+from lim import ui
+from lim.device import Device
+
+
+@dataclass(frozen=True)
+class StorageTarget:
+    """An encrypted drive plus all derived mapper/mount/partition paths."""
+
+    device: Device
+
+    @property
+    def mapper_name(self) -> str:
+        return f"encrypteddrive-{self.device.name}"
+
+    @property
+    def mapper_path(self) -> str:
+        return f"/dev/mapper/{self.mapper_name}"
+
+    @property
+    def mount_path(self) -> str:
+        return f"/media/{self.mapper_name}"
+
+    @property
+    def partition_path(self) -> str:
+        return self.device.partition(1)
+
+
+def select_storage_target() -> StorageTarget:
+    target = StorageTarget(device_module.select_device())
+    ui.info(f"mapper name set to : {target.mapper_name}")
+    ui.info(f"mapper path set to : {target.mapper_path}")
+    ui.info(f"mount path set to : {target.mount_path}")
+    return target