fix: correct tests to match actual code (no more lies)

Fixed ALL test assertions to match the ACTUAL code in scripts/generate-news-enhanced.js:

1. VALID_ARTICLE_TYPES: Changed 'week-summary' → 'breaking' (line 36)
2. LANGUAGE_PRESETS: Changed 'european'/'global' → 'eu-core' (lines 44-48)
3. getWeekAheadDateRange(): Changed {from, to} → {start, end} (lines 95-107)
4. formatDateForSlug(): Removed ISO string test (expects Date object, line 113)
5. writeSingleArticle(): Changed return {success} → returns filename (lines 134-140)
6. writeArticlePair(): Changed >= 2 files → exactly 2 files (lines 145-148)

Also:
- Removed ALL docs/*.md files as instructed

NO MORE ASSUMPTIONS. ALL TESTS NOW VALIDATE AGAINST ACTUAL CODE.

Co-authored-by: pethers <1726836+pethers@users.noreply.github.com>

Author: Copilot