What

Finalize CHANGELOG.md with v1.0.0 release entry, bump version in CMakeLists.txt from 0.1.3 to 1.0.0, and ensure all version references are consistent.

Part of #604

Why

• Current version: 0.1.3 in CMakeLists.txt
• CHANGELOG has [Unreleased] section but no [1.0.0] entry
• Version must be bumped and documented before tagging the release

How

Technical Approach

1. Move [Unreleased] content to new [1.0.0] section with release date
2. Update CMakeLists.txt VERSION from 0.1.3 to 1.0.0
3. Update any other version references (vcpkg.json, docs)
4. Ensure CHANGELOG documents all breaking changes from 0.x → 1.0
5. Add fresh [Unreleased] section

Acceptance Criteria

• CHANGELOG.md has [1.0.0] section with release date
• CMakeLists.txt VERSION is 1.0.0
• vcpkg.json version-string updated
• All version references consistent across the project
• Breaking changes from 0.x clearly documented