[MEDIUM] Create CHANGELOG.md with release history

[kilodesodiq-arch]

Engineering Gap

No CHANGELOG.md exists at repository root. Adopters and contributors cannot assess release stability, breaking changes, or version history. Commit history is the only release record.

Codebase Evidence

• No CHANGELOG.md at repo root or in docs/
• package.json declares version 1.0.0 but no changelog documents what that includes

Risk Profile

Current Risk

Adopters cannot assess release stability. Breaking changes not communicated.

Business Impact

Adoption friction. Users unaware of breaking changes. Reduced open-source credibility.

Remediation Strategy

Create CHANGELOG.md following Keep a Changelog format. Document all releases with Added, Changed, Deprecated, Removed, Fixed, Security sections.

Success Conditions

• CHANGELOG.md created at root
• Follows Keep a Changelog format
• All releases documented

Change Surface

New file: CHANGELOG.md

Security Review

No security impact.

Completion Checklist

• CHANGELOG.md created
• Ready for merge