feat: 完善水星与金星全球凌日搜索及制图导出

- 基于平均下合周期与节点相位预筛候选，减少无效星历计算；跳过无法求解的单个会合周期，避免有限覆盖星历导致搜索提前终止
- 引入影轴 γ、半影半径及地球尺度几何判定，结合站心可见性识别地心无接触、仅部分地区可见的掠凌
- 添加金星 243 年、水星 46 年周期族编号，并明确编号适用范围及未分配时的零值语义
- 为 SVG、GeoJSON 和 KML 增加站心部分凌日可见区，适配接触等时线、几何元数据、图层样式及取景；为地心无接触凌日事件增加正射图，按可见区球面面积加权居中

doc/img/transit-venus-beijing-2012.svg

@@ -1 +1 @@
-<svg xmlns="http://www.w3.org/2000/svg" width="960" height="680" viewBox="0 0 960 680" role="img" aria-label="2012-06-06 金星凌日站心图"><defs><radialGradient id="transit-sun" cx="40%" cy="34%" r="64%"><stop offset="0%" stop-color="#fff8bb"/><stop offset="58%" stop-color="#ffd55f"/><stop offset="100%" stop-color="#f5a623"/></radialGradient></defs><rect width="100%" height="100%" fill="#efefed"/><rect x="22" y="18" width="916.000" height="644.000" fill="#ffffff" stroke="#c9c9c6" stroke-width="1.2"/><text x="480.000" y="47" fill="#111111" font-family="Georgia, 'Times New Roman', serif" font-size="24" font-weight="700" text-anchor="middle">2012-06-06 金星凌日站心图</text><text x="480.000" y="72.000" fill="#333" font-family="Georgia, 'Times New Roman', serif" font-size="13" text-anchor="middle">观测地 东经 116.4074° 北纬 39.9042°，海拔 0 米</text><text x="480.000" y="91.000" fill="#333" font-family="Georgia, 'Times New Roman', serif" font-size="13" text-anchor="middle">站心完整凌日，可见 | 最小角距 544.0″ | 太阳视半径 945.3″ | 行星视半径 28.90″</text><circle class="transit-sun" cx="323.000" cy="353.000" r="213.136" fill="url(#transit-sun)" stroke="#c78211" stroke-width="1.4"/><line x1="323.000" y1="121.864" x2="323.000" y2="584.136" stroke="#8b6a2b" stroke-width="0.8" stroke-dasharray="3 4" stroke-opacity="0.7"/><line x1="91.864" y1="353.000" x2="554.136" y2="353.000" stroke="#8b6a2b" stroke-width="0.8" stroke-dasharray="3 4" stroke-opacity="0.7"/><text x="323.000" y="115.864" fill="#6b5222" font-family="Georgia, 'Times New Roman', serif" font-size="13" text-anchor="middle">北</text><text x="323.000" y="600.136" fill="#6b5222" font-family="Georgia, 'Times New Roman', serif" font-size="13" text-anchor="middle">南</text><text x="79.864" y="358.000" fill="#6b5222" font-family="Georgia, 'Times New Roman', serif" font-size="13" text-anchor="middle">东</text><text x="566.136" y="358.000" fill="#6b5222" font-family="Georgia, 'Times New Roman', serif" font-size="13" text-anchor="middle">西</text><path class="transit-track" d="M 176.376 189.451 L 178.123 189.896 L 179.871 190.341 L 181.619 190.786 L 183.368 191.231 L 185.116 191.676 L 186.866 192.121 L 188.615 192.566 L 190.364 193.011 L 191.806 193.377 L 192.114 193.456 L 193.865 193.901 L 195.615 194.345 L 197.366 194.790 L 199.117 195.235 L 200.869 195.680 L 202.620 196.124 L 204.372 196.569 L 206.125 197.014 L 207.877 197.458 L 209.630 197.903 L 211.383 198.347 L 213.137 198.792 L 214.891 199.237 L 216.645 199.681 L 218.399 200.126 L 220.154 200.570 L 221.909 201.015 L 223.664 201.459 L 225.420 201.904 L 227.175 202.348 L 228.932 202.793 L 230.688 203.237 L 232.445 203.682 L 234.202 204.126 L 235.959 204.571 L 237.717 205.015 L 239.475 205.460 L 241.233 205.904 L 242.991 206.349 L 244.750 206.793 L 246.509 207.238 L 248.268 207.682 L 250.028 208.127 L 251.788 208.572 L 253.548 209.016 L 255.308 209.461 L 257.069 209.905 L 258.830 210.350 L 260.591 210.794 L 262.353 211.239 L 264.115 211.683 L 265.877 212.128 L 267.639 212.573 L 269.402 213.017 L 271.165 213.462 L 272.928 213.907 L 274.691 214.351 L 276.455 214.796 L 278.219 215.241 L 279.983 215.685 L 281.748 216.130 L 283.512 216.575 L 285.277 217.020 L 287.043 217.465 L 288.808 217.909 L 290.574 218.354 L 292.340 218.799 L 294.106 219.244 L 295.873 219.689 L 297.640 220.134 L 299.407 220.579 L 301.174 221.024 L 302.942 221.469 L 304.709 221.914 L 306.477 222.360 L 308.246 222.805 L 310.014 223.250 L 311.783 223.695 L 313.552 224.141 L 315.321 224.586 L 317.091 225.031 L 318.860 225.477 L 320.630 225.922 L 322.400 226.368 L 324.171 226.813 L 325.941 227.259 L 327.712 227.704 L 329.483 228.150 L 331.255 228.596 L 333.026 229.041 L 334.798 229.487 L 336.570 229.933 L 338.342 230.379 L 340.114 230.825 L 341.887 231.271 L 343.660 231.717 L 345.433 232.163 L 347.206 232.609 L 348.979 233.055 L 350.753 233.501 L 352.527 233.947 L 352.927 234.048 L 354.301 234.394 L 356.075 234.840 L 357.849 235.287 L 359.624 235.733 L 361.399 236.180 L 363.174 236.626 L 364.949 237.073 L 366.724 237.519 L 368.500 237.966 L 370.275 238.413 L 372.051 238.860 L 373.827 239.307 L 375.604 239.754 L 377.380 240.201 L 379.156 240.648 L 380.933 241.095 L 382.710 241.542 L 384.487 241.990 L 386.264 242.437 L 388.042 242.884 L 389.819 243.332 L 391.597 243.779 L 393.375 244.227 L 395.153 244.675 L 396.931 245.122 L 398.709 245.570 L 400.488 246.018 L 402.266 246.466 L 404.045 246.914 L 405.824 247.362 L 407.603 247.810 L 409.382 248.258 L 411.161 248.707 L 412.940 249.155 L 414.720 249.603 L 416.499 250.052 L 418.279 250.500 L 420.059 250.949 L 421.839 251.398 L 423.619 251.847 L 425.399 252.295 L 427.179 252.744 L 428.960 253.193 L 430.740 253.642 L 432.521 254.091 L 434.301 254.541 L 436.082 254.990 L 437.863 255.439 L 439.644 255.889 L 441.425 256.338 L 443.206 256.788 L 444.987 257.237 L 446.769 257.687 L 448.550 258.137 L 450.331 258.587 L 452.113 259.037 L 453.894 259.487 L 455.676Line truncated
+<svg xmlns="http://www.w3.org/2000/svg" width="960" height="680" viewBox="0 0 960 680" role="img" aria-label="2012-06-06 金星凌日站心图"><defs><radialGradient id="transit-sun" cx="40%" cy="34%" r="64%"><stop offset="0%" stop-color="#fff8bb"/><stop offset="58%" stop-color="#ffd55f"/><stop offset="100%" stop-color="#f5a623"/></radialGradient></defs><rect width="100%" height="100%" fill="#efefed"/><rect x="22" y="18" width="916.000" height="644.000" fill="#ffffff" stroke="#c9c9c6" stroke-width="1.2"/><text x="480.000" y="47" fill="#111111" font-family="Georgia, 'Times New Roman', serif" font-size="24" font-weight="700" text-anchor="middle">2012-06-06 金星凌日站心图</text><text x="480.000" y="72.000" fill="#333" font-family="Georgia, 'Times New Roman', serif" font-size="13" text-anchor="middle">观测地 东经 116.4074° 北纬 39.9042°，海拔 0 米</text><text x="480.000" y="91.000" fill="#333" font-family="Georgia, 'Times New Roman', serif" font-size="13" text-anchor="middle">站心完整凌日，可见 | 最小角距 544.0″ | 太阳视半径 945.3″ | 行星视半径 28.90″</text><circle class="transit-sun" cx="323.000" cy="357.900" r="198.013" fill="url(#transit-sun)" stroke="#c78211" stroke-width="1.4"/><line x1="323.000" y1="147.887" x2="323.000" y2="567.913" stroke="#8b6a2b" stroke-width="0.8" stroke-dasharray="3 4" stroke-opacity="0.7"/><line x1="112.987" y1="357.900" x2="533.013" y2="357.900" stroke="#8b6a2b" stroke-width="0.8" stroke-dasharray="3 4" stroke-opacity="0.7"/><text x="323.000" y="141.887" fill="#6b5222" font-family="Georgia, 'Times New Roman', serif" font-size="13" text-anchor="middle">北</text><text x="323.000" y="583.913" fill="#6b5222" font-family="Georgia, 'Times New Roman', serif" font-size="13" text-anchor="middle">南</text><text x="100.987" y="362.900" fill="#6b5222" font-family="Georgia, 'Times New Roman', serif" font-size="13" text-anchor="middle">东</text><text x="545.013" y="362.900" fill="#6b5222" font-family="Georgia, 'Times New Roman', serif" font-size="13" text-anchor="middle">西</text><path class="transit-track" d="M 186.779 205.956 L 188.403 206.369 L 190.027 206.783 L 191.651 207.196 L 193.275 207.609 L 194.900 208.023 L 196.525 208.436 L 198.150 208.850 L 199.776 209.263 L 201.114 209.603 L 201.401 209.676 L 203.027 210.089 L 204.654 210.503 L 206.280 210.916 L 207.907 211.329 L 209.534 211.742 L 211.162 212.155 L 212.789 212.568 L 214.417 212.982 L 216.046 213.395 L 217.674 213.808 L 219.303 214.221 L 220.932 214.634 L 222.561 215.047 L 224.191 215.460 L 225.821 215.873 L 227.451 216.286 L 229.082 216.699 L 230.712 217.112 L 232.343 217.525 L 233.975 217.938 L 235.606 218.351 L 237.238 218.764 L 238.870 219.177 L 240.502 219.590 L 242.135 220.003 L 243.768 220.416 L 245.401 220.829 L 247.034 221.242 L 248.668 221.655 L 250.302 222.067 L 251.936 222.480 L 253.571 222.893 L 255.206 223.306 L 256.841 223.719 L 258.476 224.132 L 260.111 224.545 L 261.747 224.958 L 263.383 225.371 L 265.019 225.784 L 266.656 226.197 L 268.293 226.610 L 269.930 227.024 L 271.567 227.437 L 273.205 227.850 L 274.842 228.263 L 276.481 228.676 L 278.119 229.089 L 279.757 229.502 L 281.396 229.915 L 283.035 230.329 L 284.675 230.742 L 286.314 231.155 L 287.954 231.568 L 289.594 231.981 L 291.234 232.395 L 292.875 232.808 L 294.515 233.221 L 296.156 233.635 L 297.798 234.048 L 299.439 234.462 L 301.081 234.875 L 302.723 235.288 L 304.365 235.702 L 306.007 236.116 L 307.650 236.529 L 309.293 236.943 L 310.936 237.356 L 312.579 237.770 L 314.222 238.184 L 315.866 238.597 L 317.510 239.011 L 319.154 239.425 L 320.798 239.839 L 322.443 240.253 L 324.088 240.667 L 325.733 241.081 L 327.378 241.495 L 329.023 241.909 L 330.669 242.323 L 332.315 242.737 L 333.961 243.151 L 335.607 243.565 L 337.253 243.979 L 338.900 244.394 L 340.547 244.808 L 342.194 245.222 L 343.841 245.637 L 345.488 246.051 L 347.136 246.466 L 348.784 246.880 L 350.432 247.295 L 350.803 247.388 L 352.080 247.709 L 353.728 248.124 L 355.377 248.539 L 357.025 248.954 L 358.674 249.368 L 360.323 249.783 L 361.972 250.198 L 363.622 250.613 L 365.271 251.028 L 366.921 251.443 L 368.571 251.859 L 370.221 252.274 L 371.871 252.689 L 373.521 253.104 L 375.172 253.520 L 376.823 253.935 L 378.473 254.351 L 380.124 254.766 L 381.775 255.182 L 383.427 255.598 L 385.078 256.013 L 386.730 256.429 L 388.381 256.845 L 390.033 257.261 L 391.685 257.677 L 393.337 258.093 L 394.989 258.509 L 396.642 258.925 L 398.294 259.341 L 399.947 259.758 L 401.600 260.174 L 403.252 260.590 L 404.905 261.007 L 406.559 261.423 L 408.212 261.840 L 409.865 262.257 L 411.518 262.673 L 413.172 263.090 L 414.826 263.507 L 416.479 263.924 L 418.133 264.341 L 419.787 264.758 L 421.441 265.175 L 423.095 265.592 L 424.750 266.009 L 426.404 266.427 L 428.058 266.844 L 429.713 267.262 L 431.367 267.679 L 433.022 268.097 L 434.677 268.514 L 436.332 268.932 L 437.987 269.350 L 439.642 269.768 L 441.297 270.186 L 442.952 270.604 L 444.607 271.022 L 446.2Line truncated