docs: standardize markdown filenames to lowercase-with-hyphens

- Renamed all documentation files to use lowercase-with-hyphens format
  for consistency across the monorepo
- Removed session diary docs (progress summaries and test status reports)
  from packages/cli/.claude/ directory
- Kept state-of-the-nation style technical reports and architecture docs

Files renamed (14):
- .config/INDEX.md → index.md
- .config/QUICK_REFERENCE.md → quick-reference.md
- docs/BUILD_QUICK_START.md → build-quick-start.md
- docs/BUILDS_CREATED.md → builds-created.md
- packages/cli/test/helpers/EXAMPLES.md → examples.md
- packages/cli/test/helpers/SDK_TESTING.md → sdk-testing.md
- packages/sbom-generator/ARCHITECTURE.md → architecture.md
- packages/sbom-generator/ECOSYSTEMS.md → ecosystems.md
- packages/sbom-generator/FIDELITY-ANALYSIS.md → fidelity-analysis.md
- packages/sbom-generator/IMPLEMENTATION.md → implementation.md
- packages/sbom-generator/LOCK-STEP-COMPLIANCE.md → lock-step-compliance.md
- packages/yoga-layout/research/API_COMPATIBILITY.md → api-compatibility.md
- packages/yoga-layout/research/TAFFY-RESEARCH.md → taffy-research.md
- packages/yoga-layout/research/TESTING.md → testing.md

Files removed (2):
- packages/cli/.claude/progress-summary.md (session diary)
- packages/cli/.claude/test-status-report.md (session diary)

Author: jdalton