[codex] Add tests and lint CI

[Faolain]

Summary

Adds a dedicated GitHub Actions workflow for local JS quality checks, with separate lint and Vitest steps.

Also adds ESLint flat config and fixes the existing explicit any usage so @typescript-eslint/no-explicit-any can run as an active lint rule instead of being suppressed.

Details

• Adds lint and test:ci package scripts.
• Adds ESLint dependencies and eslint.config.js.
• Adds .github/workflows/tests-and-lint.yml for all pull requests and pushes to main.
• Replaces explicit any usage with concrete object types, unknown, jaxray selection types, and typed STAC metadata accessors.
• Removes a focused Haversine test marker and fixes stale distance assertions that CI exposed.
• Cleans up minor lint issues discovered while enabling the gate.

Validation

• corepack yarn lint
• corepack yarn build
• CI=1 corepack yarn test:ci