Add web interface section to README describing all pages (dashboard,
package browser, source browser, version diff). Add monitoring section
with the full Prometheus metrics table and scrape config. Add cooldown
column to the registry support table. Update architecture doc with
accurate database schema including all columns and indexes, and add
entries for metrics, cooldown, and enrichment packages.
Hides package versions published too recently from metadata responses,
giving the community time to spot malicious releases. Configurable
per-ecosystem and per-package with duration overrides. Supported for
npm, PyPI, pub.dev, and Composer.