feat: add validation audit and best practice gap analysis to spec-analyzer

fix: add missing frontmatter opener in test-case-creator

docs: add CLAUDE.md for AI agent onboarding

feat: add black box testing techniques to test-case-creator

feat: replace SVG logo with PNG for GitHub compatibility

feat: add Argus logo and display in README

docs: replace ASCII diagram with Mermaid for proper rendering on GitHub

docs: redesign architecture diagram for better readability

docs: update README with report-exporter skill and scripts/ folder

feat: add permanent export-testcase.py script with reference-matching styling

docs: add test case xlsx export example reference

feat: register report-exporter in using-argus skill table

feat: add report-exporter skill (SKILL.md)

chore: gitignore entire docs/ folder (local only)

feat: redesign spec-analyzer with multi-file input and analysis report