feat: add type hints, new CLI features, and improve project structure

chore: add uv.lock to gitignore

Major changes:
- Add type hints and docstrings to all functions (PEP 484)
- Add __main__.py for module execution (python -m genpass)
- Expose public API in __init__.py
- Add config file support (~/.genpass/config.json)
- Add entropy calculation (--entropy)
- Add clipboard support (--clipboard/-c)
- Add ambiguous characters exclusion (--no-ambiguous)
- Add output formats: plain, json, delimited (--format)
- Add sensible defaults (all character types enabled by default)
- Add input validation for length and count
- Update shell completions for all new options
- Add pre-commit config with ruff, mypy, black
- Update pyproject.toml with dev dependencies and tool configs
- Add requirements.txt and requirements-dev.txt
- Update README.md with comprehensive examples

BREAKING CHANGE: Default behavior now includes all character types

genpass/__init__.py

@@ -0,0 +1,30 @@
+"""
+GenPass - Secure password generator.
+
+This package provides functionality to generate strong, random passwords
+with customizable character sets and various security features.
+
+Example usage:
+    >>> from genpass import generate_password, get_character_pools
+    >>> pools = get_character_pools(True, True, True, True, "!@#$%", False)
+    >>> password = generate_password(16, pools)
+    >>> print(password)
+"""
+
+from genpass.cli import (
+    AMBIGUOUS_CHARS,
+    DEFAULT_SYMBOLS,
+    calculate_entropy,
+    generate_password,
+    get_character_pools,
+)
+
+__version__ = "2.0.0"
+__all__ = [
+    "generate_password",
+    "get_character_pools",
+    "calculate_entropy",
+    "DEFAULT_SYMBOLS",
+    "AMBIGUOUS_CHARS",
+    "__version__",
+]