chore(project): add pyproject.toml and project configuration

Configure Python project with pydantic, structlog, typer, rich dependencies.
Set up ruff, mypy, pytest tooling with strict type checking.

changelog.md

@@ -0,0 +1,17 @@
+# Changelog
+
+All notable changes to Veritext will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+### Added
+
+- Project scaffold with pyproject.toml and development tooling
+- Core exception hierarchy (`VeritextError` and subclasses)
+- Core types: `ValidationContext`, `CheckResult`, `ValidationResult`
+- Word tokeniser with Unicode normalisation support
+- Configuration module with pydantic-settings
+- Structured logging with structlog