📋 Add architectural principles and patterns document

Comprehensive guide covering:
- Core philosophy (heart-centered engineering, universal love)
- Visibility principle (errors surface in testing, not production)
- Observability by design (structured logging, Sentry tracing, breadcrumbs)
- Integration patterns (progressive disclosure, service adapters, credential polymorphism, meta-modeling)
- Tech stack decisions (Python/TypeScript, sync by default, database choices, tooling)
- Code organization, testing, git workflow, naming conventions

Canonical source for architectural principles across all projects.

🤖 Generated with Claude Code

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: Nick Sullivan