docs(se): add SE-15 Foundational Coding Principles article
Adds a new article covering 25 core coding principles missing from the
existing SE series:
- KISS, YAGNI, DRY
- Separation of Concerns, Encapsulation, Abstraction, Modularity
- High Cohesion / Low Coupling
- Boy Scout Rule, Fail Fast, Defensive Programming
- Principle of Least Astonishment
- Automation, Immutability, Observability
- Performance as a Feature, Concurrent & Parallel Thinking
- Documentation is Part of the Code, Feedback Loops
- Summary mottoes and a "How These Principles Interact" section
Updates SE-01, SE-14, and the index to link to the new article.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
docs: add 14-article Software Engineering Principles series
Full series covering: Introduction to SE, SDLC, OOP, SOLID Principles,
Design Patterns (GoF), Clean Code, Software Architecture, Refactoring,
Testing Principles, Version Control & Git Workflows, API Design,
Security Principles (OWASP Top 10), Database Design, Agile & Scrum.
Each article includes detailed explanations, Java code examples, and
forward/back navigation. Index updated with reading paths by task.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>