feat: 引入可切换星历模型并扩展天象观测链路

- 新增半解析、旧模型、自定义与多源堆叠星历实例，提供 Context、Instance、SPK 读取及状态与视位置计算
- 统一太阳、月球和行星实例接口，扩展黄经穿越、留、相位、最近角距、偕日可见、任意高度升落、轨道节点及凌日等天象查询
- 完善日月食、月掩与凌日的月缘剖面、有限盘面接触、站心修正、局地可见性、全球路径和地图输出
- 新增 SVG、GeoJSON、KML 天象输出及凌日、月掩和月缘地形相关缓存与几何求解
- 新增恒星星表导入与查询，支持 CSV、Hipparcos、BSC5、Stellarium 等格式及名称、交叉标识、锥面检索和星等过滤
- 补充 IAU 2006、地球定向、折射消光、大气观测、轨道传播及半解析行星/月球数据支持
- 将默认未来民用时标切换为 TimeScaleLeapHour，更新 2027–2400 农历速查表、中文日期解析和时区边界处理
- 增加事件基线、跨模型回归、几何边界、月缘地形和输出契约测试，完善中英文手册、示例资源、NOTICE 与忽略规则

moon/svg/occultation_local.go

@@ -1,6 +1,7 @@
 package svg
 
 import (
+	"b612.me/astro/internal/limbnote"
 	"b612.me/astro/internal/timenote"
 	"errors"
 	"fmt"
@@ -254,7 +255,7 @@ func renderLocalStarOccultationSVG(
 	writeLocalStarOccultationOverview(&b, diagram, events, layout, options)
 	writeLocalStarOccultationContacts(&b, events, layout, options)
 	writeLocalStarOccultationStages(&b, events, layout, options)
-	writeLocalStarOccultationFooter(&b, layout, options, info.Greatest)
+	writeLocalStarOccultationFooter(&b, layout, options, info.Greatest, info.LunarLimbApplied)
 	b.WriteString(`</svg>`)
 	return b.String()
 }
@@ -374,6 +375,8 @@ func writeLocalStarOccultationTrack(
 		}
 		fmt.Fprintf(&path, "%s %.3f %.3f ", command, mapX(frame.StarXArcsec), mapY(frame.StarYArcsec))
 	}
+	// 白色衬底保证轨迹叠在暗月面与亮月面上都可见。
+	fmt.Fprintf(b, `<path class="local-star-track-halo" d="%s" fill="none" stroke="#ffffff" stroke-width="3.6" stroke-linecap="round" opacity="0.7"/>`, strings.TrimSpace(path.String()))
 	fmt.Fprintf(b, `<path class="local-star-track" d="%s" fill="none" stroke="#9b3f36" stroke-width="1.7" stroke-dasharray="5 4" opacity="0.82" marker-end="url(#local-occultation-arrow)"/>`, strings.TrimSpace(path.String()))
 }
 
@@ -469,12 +472,22 @@ func writeLocalStarOccultationAxes(b *strings.Builder, cx, cy, radius float64, l
 	}
 }
 
+// 被掩目标轮廓用浅金色，配暗色衬底，暗月面与亮月面上都能分辨。
+const localOccultationHiddenOutlineColor = "#f3d48e"
+
+func writeLocalOccultationHiddenOutlineHalo(b *strings.Builder, x, y, radius float64) {
+	fmt.Fprintf(b, `<circle class="hidden-outline-halo" cx="%.3f" cy="%.3f" r="%.3f" fill="none" stroke="#1a1c1e" stroke-width="3" opacity="0.55"/>`, x, y, radius)
+}
+
 func writeLocalStarOccultationStar(b *strings.Builder, x, y float64, hidden bool, class, label string) {
 	fill, stroke, dash := "#fff7d6", "#9b3028", ""
 	if hidden {
-		fill, stroke, dash = "none", "#7d3430", ` stroke-dasharray="2 2"`
+		fill, stroke, dash = "none", localOccultationHiddenOutlineColor, ` stroke-dasharray="3 2"`
 	}
 	fmt.Fprintf(b, `<g class="%s" data-label="%s">`, html.EscapeString(class), html.EscapeString(label))
+	if hidden {
+		writeLocalOccultationHiddenOutlineHalo(b, x, y, 4.2)
+	}
 	fmt.Fprintf(b, `<circle cx="%.3f" cy="%.3f" r="4.2" fill="%s" stroke="%s" stroke-width="1.4"%s/>`, x, y, fill, stroke, dash)
 	fmt.Fprintf(b, `<line x1="%.3f" y1="%.3f" x2="%.3f" y2="%.3f" stroke="%s" stroke-width="1"/>`, x-6, y, x+6, y, stroke)
 	fmt.Fprintf(b, `<line x1="%.3f" y1="%.3f" x2="%.3f" y2="%.3f" stroke="%s" stroke-width="1"/>`, x, y-6, x, y+6, stroke)
@@ -558,11 +571,13 @@ func writeLocalStarOccultationFooter(
 	layout localStarOccultationSVGLayout,
 	options LocalStarOccultationSVGOptions,
 	instant time.Time,
+	limbApplied bool,
 ) {
 	directionLines, footerLines := localOccultationFooterLines(
 		localStarOccultationSVGDirectionText(options),
 		localStarOccultationSVGFooterNote(options),
-		timenote.Scale(options.TimeScale, instant, options.Location, options.Language),
+		limbnote.Join(timenote.Scale(options.TimeScale, instant, options.Location, options.Language),
+			limbnote.Contacts(limbApplied, options.Language), options.Language),
 		layout.footerY, layout.width, layout.height)
 	for index, line := range directionLines {
 		fmt.Fprintf(b, `<text x="%.3f" y="%.3f" fill="#4f595b" font-family="Georgia, 'Times New Roman', serif" font-size="10">%s</text>`,