Expand AI stack production guide

[brunoaureli]

Summary

• add a human-facing architecture guide with executive summary, component boundaries, and a production build sequence
• add a fetch-first source ledger for current official documentation and repositories
• add Turso persistence, OpenTelemetry-compatible telemetry, evaluations, durable work, identity, and operational guidance to the installable skill
• add a validation report that separates repository checks from application acceptance evidence

Why

The stack previously listed useful components but lacked a cohesive production philosophy, explicit integration boundaries, operational observability, and a durable source/validation structure.

Validation

• git diff --check
• skill YAML frontmatter validation
• balanced Markdown fence validation
• HTTP 200 checks for all source-ledger documentation URLs
• fresh-task skill forward test for a regulated contract-review workflow