v0.3.1 — KMZ 疊圖修復

What's New

KMZ 疊圖修復（fixes #1）

• 修正 doc.kml 結構：所有 3km 圖磚的 <GroundOverlay> 直接平鋪寫入（對齊 PHP GarminKmz 原始行為）
• 舊版將所有 tile 放在單一不合法的 <NetworkLink>（小寫 <link>）中，檢視器只會載入第一塊 3×3 km 圖磚，造成「downloaded kmz only shows 3x3 area」
• KMZ 寫入時記錄格數與涵蓋範圍（例：3×4 km 範圍 → 1×2 塊、涵蓋 3×4 km）
• 新增 tests/test_kmz.py：固定 tile 數（ceil(寬/3) × ceil(高/3)）、doc.kml 結構（無 NetworkLink）與完整覆蓋範圍
• README 說明 KMZ 圖磚固定 3×3 km、與列印頁面尺寸（dim）無關

English

• Fix KMZ doc.kml: every 3 km tile's <GroundOverlay> is now written inline, matching the PHP GarminKmz original
• Previously all tiles were routed through a single malformed <NetworkLink> (lowercase <link> children), so viewers loaded only the first 3×3 km tile
• KMZ export now logs the tile grid and covered extent
• New tests pinning tile counts, doc.kml structure and full-region coverage
• README documents that KMZ tiles are a fixed 3×3 km grid, independent of the print page dimension