Add books and documentation tools

[QDenka]

Summary

Add 5 curated resources that fill identified gaps in the collection:

Design Documentation (2 resources):

• Structurizr — Official C4 tooling by Simon Brown, complements the existing C4 Model entry with concrete architecture-as-code tooling.
• PlantUML — The most established diagrams-as-code tool, a notable omission given we already list D2, Mermaid, and Diagrams.

Books (3 resources):

• Release It! (2nd Edition) — Fills a gap on production resilience and stability patterns (circuit breakers, bulkheads). Author (Nygard) is already referenced in the ADR section.
• Team Topologies — Conway's Law applied practically. No existing entry covers the org-design/architecture relationship.
• Balancing Coupling in Software Design — Three-dimensional coupling model. Author (Khononov) already present with "Learning DDD".

Why

Each resource was evaluated against existing entries for uniqueness, relevance to the repo's scope ("organizing and structuring software through patterns, decisions, and verified design rules"), and author credibility. One proposed resource (Papers We Love) was rejected as too tangential.

Checklist

• Follows format: [Resource Name](link) - Description.
• Added to the bottom of relevant sections
• No duplicates with existing entries
• Descriptions are short, start with capital, end with period