chore(scripts): extract shared utils, add tests, enforce standards

[zrosenbauer]

Summary

• Extract shared utilities into scripts/lib/ (frontmatter, config, status, ansi, diff) eliminating ~100 lines of duplication across the three .lauf.ts scripts
• Add vitest test infrastructure with 66 tests across 9 test files covering all pure functions
• Remove optional chaining (?.), ternaries, and for loops from pure logic by extracting helper functions
• Replace local utility copies with shared lib imports in all three .lauf.ts scripts
• Replace inline ANSI colors and manual diff rendering with shared ANSI constant and displayDiff function
• Add Result tuple error handling for readProjectConfig call sites

Changes

Phase 1: Test Infrastructure

• Added vitest devDependency and test script to package.json
• Created scripts/vitest.config.ts

Phase 2: Shared Utility Extraction

• scripts/lib/frontmatter.ts — parseFrontmatter, updateFrontmatter, extractTitle, FRONTMATTER_RE
• scripts/lib/config.ts — readProjectConfig (Result tuple), FEATURES_DIR, config types
• scripts/lib/status.ts — reverseStatusMapping
• scripts/lib/ansi.ts — consolidated ANSI escape codes
• Fixed backup.ts dynamic imports and product-area-colors.ts duplicate key

Phase 3: Tests (66 total)

• frontmatter.test.ts (10), config.test.ts (3), status.test.ts (3), diff.test.ts (3)
• product-area-colors.test.ts (4), query-loader.test.ts (2)
• features.test.ts (5), project.test.ts (17), readme.test.ts (19)

Phase 4: Standards Compliance

• Replaced all ?. with explicit null checks
• Replaced all ternaries with helper functions (resolveVisibility, formatStatusLabel, conditionalValue, etc.)
• Converted Map-building for loops to new Map(items.filter.map) pattern
• ~30 helper functions extracted across the three scripts

Shared Lib Integration

• All three .lauf.ts files now import from shared libs instead of local copies
• Removed yaml import from features.lauf.ts and readme.lauf.ts
• Removed local ProjectConfig, FeaturesConfig, ConfigField, ConfigView type definitions
• Replaced inline diff display in project.lauf.ts with displayDiff

Test plan

• pnpm test — 66/66 tests pass
• pnpm lint — 0 warnings, 0 errors
• pnpm format:check — all files formatted
• npx tsc -p scripts/tsconfig.json --noEmit — 0 TypeScript errors
• Pre-commit hooks pass (lint, format, commitlint)