feat: Implement HEIC/HEIF parsing and rebuilding utilities

- Add `heic_types.py` to define structures for HEIC/HEIF boxes including ItemLocationBox, ItemInfoEntryBox, and others.
- Introduce parsing logic in `parser.py` to handle various box types and their contents, including nested structures.
- Implement rebuilding functionality for ItemLocationBox to adjust offsets based on new metadata.
- Enhance ItemInfoBox to correctly parse and build content for ItemInfoEntry.
- Update `pyproject.toml` to include project metadata and dependencies.

pyproject.toml

@@ -0,0 +1,30 @@
+[project]
+name = "pyheic-struct"
+version = "0.1.0"
+description = "Low-level utilities for parsing and rebuilding HEIC/HEIF files, with Samsung-to-Apple motion photo conversion helpers."
+authors = [
+    { name = "Your Name", email = "you@example.com" }
+]
+license = { text = "MIT" }
+readme = "README.md"
+requires-python = ">=3.10"
+dependencies = [
+    "Pillow>=10.0.0",
+    "pillow-heif>=0.15.0",
+]
+
+[project.optional-dependencies]
+full = [
+    "exiftool-wrapper>=0.5.0",
+]
+
+[project.scripts]
+pyheic-struct = "pyheic_struct.cli:main"
+
+[build-system]
+requires = ["setuptools>=61.0"]
+build-backend = "setuptools.build_meta"
+
+[tool.setuptools.packages.find]
+where = ["."]
+include = ["pyheic_struct*"]