docs: add the canonical public-repository community health baseline

[homeofe]

Context

The weekly estate-health review in elvatis/ideabase#38 found that this public TypeScript repository has none of the canonical community-health files. In particular, the absence of a license leaves reuse terms undefined.

Acceptance criteria

• Add an Apache-2.0 LICENSE with the canonical 2026 Elvatis copyright line
• Declare Apache-2.0 in package metadata where applicable
• Add SECURITY.md with the security@elvatis.com reporting path and supported-version policy
• Add CODE_OF_CONDUCT.md using the estate Contributor Covenant baseline
• Add CONTRIBUTING.md adapted to the real build, test, lint, and pull-request workflow
• Add bug and feature issue templates
• Add a pull-request template with test, security, documentation, and breaking-change checks
• Verify every command and contact address against the repository before merge

Source of truth

Follow the public-repository baseline in Ideabase project conventions section 5. Do not copy commands or package assumptions that this repository does not actually support.