Bump version to 2.0.0

Breaking change: __init__.py renamed to ksuid.py (import path unchanged).
New features: lowercase base36, secure tokens, __slots__, Python 3.9+.
See CHANGELOG.md for full details.

https://claude.ai/code/session_01PVPVUNWhpxVa3xbDDBnwp2

Author: claude

CHANGELOG.md

@@ -5,6 +5,45 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [2.0.0] - 2026-02-06
+
+### Added
+- Lowercase base36 encoding (`0-9a-z`, 31 characters) for case-insensitive contexts
+- `KSUID.to_base36()` / `KSUID.from_base36()` instance and class methods
+- `generate_lowercase()` — sortable KSUID as lowercase base36 string
+- `generate_token()` — secure 160-bit random token (no timestamp), base62
+- `generate_token_lowercase()` — secure 160-bit random token, base36
+- `from_base36()` module-level convenience function
+- `__slots__` on KSUID class for memory efficiency
+- Thread-safety tests (concurrent generation across 4 threads)
+- CI matrix: Python 3.9, 3.10, 3.11, 3.12, 3.13, 3.14
+- CLI `--count` upper bound (1,000,000) to prevent memory exhaustion
+- Edge-case tests: zero-value round-trip, max-timestamp round-trip, base62 overflow
+
+### Fixed
+- `_base62_decode` raised uncontrolled `OverflowError` on crafted input exceeding 20-byte max; now raises `ValueError`
+- `_base62_encode` returned single-char `"0"` for all-zero input instead of 27-char padded string
+- `__eq__` returned `False` instead of `NotImplemented` for non-KSUID types
+- `PrefixedKSUID.create` allowed underscores in prefixes but `parse` couldn't round-trip them
+- CI workflow referenced nonexistent `python -m ksuid.cli` module path
+- KSUID epoch comment said "January 1, 2014" but value is May 13, 2014
+- Flaky smoke test using 1ms sleep for 1-second resolution timestamps
+- Unicode emoji in print statements caused `UnicodeEncodeError` on Windows (cp1252)
+- `_validate_count` raised `ValueError` instead of `ArgumentTypeError` for non-numeric input
+
+### Changed
+- **BREAKING**: Renamed `__init__.py` to `ksuid.py` (fixes Windows imports; `from ksuid import ...` still works)
+- Minimum Python version lowered from 3.13 to 3.9
+- `_base62_decode` uses O(1) dict lookup instead of O(n) `str.index()`
+- `create_api_key()` / `create_session_id()` now use `generate_token()` (no timestamp leakage)
+- Upgraded `actions/setup-python` from v4 to v5
+- Removed `sys.path.insert` hacks from all files
+- Applied `black` formatting across entire codebase
+
+### Security
+- `generate_token()` / `generate_token_lowercase()` use `secrets.token_bytes` for 160-bit entropy with no embedded timestamp
+- Added security warnings to `create_api_key()` / `create_session_id()` docstrings
+
 ## [1.0.0] - 2025-07-02
 
 ### Added
@@ -16,23 +55,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Zero external dependencies
 - Command-line interface (CLI) with generate, inspect, compare, and benchmark commands
 - Stripe-style prefixed ID examples and utilities
-- Comprehensive test suite with 268 test cases
-- Performance benchmarks (459,856+ KSUIDs/second with Python 3.13)
+- Comprehensive test suite
+- Performance benchmarks
 - Complete API documentation and usage examples
-- Production-ready Flask API examples
-- Database integration examples (SQLite)
-- Industry adoption documentation and best practices
-
-### Performance
-- Generation: 459,856 KSUIDs/second
-- String parsing: 136,803 parses/second  
-- Bytes parsing: 821,620 parses/second
-- Comparisons: 4.7M comparisons/second
 
 ### Compatibility
 - Python 3.13+ support
 - Cross-platform compatibility (Windows, macOS, Linux)
 - Thread-safe concurrent generation
 - Hashable for use in sets and dictionaries
 
-[1.0.0]: https://github.com/tototheo/ksuid-python/releases/tag/v1.0.0
+[2.0.0]: https://github.com/tonyzorin/ksuid-python/compare/v1.0.0...v2.0.0
+[1.0.0]: https://github.com/tonyzorin/ksuid-python/releases/tag/v1.0.0

ksuid.py

@@ -25,7 +25,7 @@
 from datetime import datetime, timezone
 from typing import Optional
 
-__version__ = "1.0.0"
+__version__ = "2.0.0"
 __all__ = [
     "KSUID",
     "generate",