refactor: architecture cleanup — OCP-compliant CSS, data-driven nav, test suite

[ronaldtse]

Summary

Architecture cleanup implementing all 8 recommendations from the code quality audit.

Changes

OCP-compliant CSS (~90 selectors → 6 generic rules)

• Replaced per-type/per-stage CSS selectors with inline CSS custom properties (--stage-color, --doctype-color, --badge-color, --cat-color)
• Templates set variables via Liquid; CSS consumes them generically
• Adding a new stage or doctype = adding a CSS variable, zero CSS rule changes

Data-driven navigation

• Extracted _data/navigation.yml as single source of truth for categories and draft stages
• Header, footer, and home page all iterate from this data
• Drafts page uses stage_filter_name: draft_stages instead of hardcoded stage list

JSON Schema for data contract

• Added _data/schemas/documents.schema.json defining the expected shape of aggregated document data
• Rake task rake validate_schema validates _data/documents.json against the schema

RSpec test suite (26 examples)

• config_spec — Jekyll config structure, excludes, keep_files
• rake_spec — all Rake tasks defined
• schema_spec — document data satisfies JSON Schema, field assertions
• data_integrity_spec — navigation ↔ data consistency, document ID uniqueness
• template_spec — no references to archived layouts/includes, data-driven nav wired correctly

Cleanup

• Archived unused layouts (toc.html, toc-type.html, document.html) and includes (toc-*, disqus_comments, feedback, script, find-doc) to _archive/
• Removed dead documents collection from _config.yml
• Updated .gitignore to exclude entire public/ directory
• Removed stale public/assets/relaton.css

Verification

• Full rake build succeeds (aggregate → Vite → Jekyll)
• All 5 listing pages render with correct document counts
• Home page renders data-driven category cards
• CSS variables correctly applied on all document cards
• 26 RSpec examples pass