refactor(package): rename to dm_imu and restructure directories

Renamed package from dm_imu_pkg to dm_imu across PKG-INFO, egg-info files,
and directories. Updated CMakeLists.txt, __init__.py, and top_level.txt to
reflect new structure. Bumped gradio version from <5.0 to <6.0 in
dependencies. This refactoring improves naming consistency and streamlines
the package layout for better maintainability.

dm_imu/__init__.py

@@ -0,0 +1,47 @@
+import pathlib
+import importlib.util
+import sys
+
+def _load_imu_module():
+    """
+    Load the compiled pybind11 module ``imu_py``.
+    The shared object should be placed in the ``build`` directory next to this ``__init__.py``.
+    """
+    # 1. Try to import if the .so is already in the package directory.
+    try:
+        from . import imu_py  # type: ignore  # pylint: disable=import-error
+        return imu_py
+    except Exception:
+        pass
+
+    # 2. Fallback: locate the build output relative to the package root.
+    possible_paths = [
+        pathlib.Path(__file__).parent / "build" / "imu_py.cpython-310-darwin.so",
+        pathlib.Path(__file__).parent / "build" / "imu_py.cpython-312-darwin.so",
+        # Generic pattern for other Python versions / architectures
+        pathlib.Path(__file__).parent / "build" / "imu_py.*.so",
+    ]
+
+    for p in possible_paths:
+        # glob pattern handling for the generic case
+        if "*" in str(p):
+            matches = list(p.parent.glob(p.name))
+            if matches:
+                p = matches[0]
+            else:
+                continue
+        if p.is_file():
+            spec = importlib.util.spec_from_file_location("imu_py", p)
+            imu_py = importlib.util.module_from_spec(spec)
+            spec.loader.exec_module(imu_py)  # type: ignore
+            return imu_py
+
+    raise ImportError(
+        "Unable to locate the compiled 'imu_py' module. "
+        "Make sure the package is installed with the compiled extension "
+        "or run the build step before importing."
+    )
+
+# Expose the DmImu class at package level for convenience
+_imu_mod = _load_imu_module()
+DmImu = _imu_mod.DmImu