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-mercury-beijing-2032.svg

@@ -1 +1 @@
-<svg xmlns="http://www.w3.org/2000/svg" width="960" height="680" viewBox="0 0 960 680" role="img" aria-label="2032-11-13 水星凌日站心图"><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">2032-11-13 水星凌日站心图</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 568.3″ | 太阳视半径 969.4″ | 行星视半径 4.97″</text><circle class="transit-sun" cx="323.000" cy="353.000" r="224.565" fill="url(#transit-sun)" stroke="#c78211" stroke-width="1.4"/><line x1="323.000" y1="110.435" x2="323.000" y2="595.565" stroke="#8b6a2b" stroke-width="0.8" stroke-dasharray="3 4" stroke-opacity="0.7"/><line x1="80.435" y1="353.000" x2="565.565" y2="353.000" stroke="#8b6a2b" stroke-width="0.8" stroke-dasharray="3 4" stroke-opacity="0.7"/><text x="323.000" y="104.435" fill="#6b5222" font-family="Georgia, 'Times New Roman', serif" font-size="13" text-anchor="middle">北</text><text x="323.000" y="611.565" fill="#6b5222" font-family="Georgia, 'Times New Roman', serif" font-size="13" text-anchor="middle">南</text><text x="68.435" y="358.000" fill="#6b5222" font-family="Georgia, 'Times New Roman', serif" font-size="13" text-anchor="middle">东</text><text x="577.565" 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 102.409 305.167 L 104.936 304.071 L 105.021 304.034 L 107.463 302.974 L 109.989 301.878 L 112.515 300.781 L 115.042 299.685 L 117.568 298.588 L 120.095 297.492 L 122.621 296.396 L 125.147 295.300 L 127.674 294.203 L 130.200 293.107 L 132.726 292.011 L 135.252 290.915 L 137.778 289.819 L 140.305 288.723 L 142.831 287.627 L 145.357 286.531 L 147.883 285.435 L 150.409 284.339 L 152.935 283.243 L 155.461 282.147 L 157.986 281.051 L 160.512 279.956 L 163.038 278.860 L 165.564 277.764 L 168.090 276.668 L 170.615 275.573 L 173.141 274.477 L 175.667 273.382 L 178.192 272.286 L 180.718 271.191 L 183.243 270.095 L 185.769 269.000 L 188.294 267.905 L 190.820 266.809 L 193.345 265.714 L 195.870 264.619 L 198.396 263.524 L 200.921 262.429 L 203.446 261.333 L 205.971 260.238 L 208.496 259.143 L 211.021 258.048 L 213.546 256.953 L 216.071 255.859 L 218.596 254.764 L 221.121 253.669 L 223.646 252.574 L 226.171 251.479 L 228.696 250.385 L 231.220 249.290 L 233.745 248.195 L 236.270 247.101 L 238.794 246.006 L 241.319 244.912 L 243.843 243.817 L 246.368 242.723 L 248.892 241.629 L 251.416 240.534 L 253.941 239.440 L 256.465 238.346 L 258.989 237.252 L 261.513 236.158 L 264.037 235.064 L 266.561 233.970 L 269.085 232.876 L 270.642 232.201 L 271.609 231.782 L 274.133 230.688 L 276.657 229.594 " fill="none" stroke="#24518a" stroke-width="1.4" stroke-dasharray="none" stroke-linecap="round"/><path class="transit-track-below-horizon" d="M 276.657 229.594 L 279.181 228.500 L 281.704 227.406 L 284.228 226.313 L 286.752 225.219 L 289.275 224.125 L 291.799 223.032 L 294.322 221.938 L 296.846 220.845 L 299.369 219.751 L 301.892 218.658 L 304.416 217.565 L 306.939 216.471 L 309.462 215.378 L 311.985 214.285 L 314.508 213.192 L 317.031 212.099 L 319.554 211.006 L 322.077 209.913 L 324.600 208.820 L 327.123 207.727 L 329.646 206.634 L 332.168 205.541 L 334.691 204.448 L 337.213 203.356 L 339.736 202.263 L 342.258 201.170 L 344.781 200.078 L 347.303 198.985 L 349.825 197.893 L 352.348 196.800 L 354.870 195.708 L 357.392 194.616 L 359.914 193.524 L 362.436 192.431 L 364.958 191.339 L 367.480 190.247 L 370.002 189.155 L 372.524 188.063 L 375.045 186.971 L 377.567 185.879 L 380.089 184.788 L 382.610 183.696 L 385.132 182.604 L 387.653 181.513 L 390.175 180.421 L 392.696 179.329 L 395.217 178.238 L 397.739 177.147 L 400.260 176.055 L 402.781 174.964 L 405.302 173.873 L 407.823 172.781 L 410.344 171.690 L 412.865 170.599 L 415.386 169.508 L 417.907 168.417 L 420.427 167.326 L 422.948 166.235 L 425.469 165.145 L 427.989 164.054 L 430.510 162.963 L 433.030 161.872 L 435.551 160.782 L 436.312 160.453 L 438.071 159.691 L 438.922 159.323 " fill="none" stroke="#8a8a8a" stroke-width="1.4" stroke-dasharray="5 4" stroke-linecap="round"/><circle class="transit-planet-c1" cx="102.409" cy="305.167" r="2.000" fill="#1d1d1d" fill-opacity="0.92" stroke="#000000" stroke-width="0.8"/><circlLine truncated
+<svg xmlns="http://www.w3.org/2000/svg" width="960" height="680" viewBox="0 0 960 680" role="img" aria-label="2032-11-13 水星凌日站心图"><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">2032-11-13 水星凌日站心图</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 568.3″ | 太阳视半径 969.4″ | 行星视半径 4.97″</text><circle class="transit-sun" cx="323.000" cy="357.900" r="208.632" fill="url(#transit-sun)" stroke="#c78211" stroke-width="1.4"/><line x1="323.000" y1="137.268" x2="323.000" y2="578.532" stroke="#8b6a2b" stroke-width="0.8" stroke-dasharray="3 4" stroke-opacity="0.7"/><line x1="102.368" y1="357.900" x2="543.632" y2="357.900" stroke="#8b6a2b" stroke-width="0.8" stroke-dasharray="3 4" stroke-opacity="0.7"/><text x="323.000" y="131.268" fill="#6b5222" font-family="Georgia, 'Times New Roman', serif" font-size="13" text-anchor="middle">北</text><text x="323.000" y="594.532" fill="#6b5222" font-family="Georgia, 'Times New Roman', serif" font-size="13" text-anchor="middle">南</text><text x="90.368" y="362.900" fill="#6b5222" font-family="Georgia, 'Times New Roman', serif" font-size="13" text-anchor="middle">东</text><text x="555.632" 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 118.061 313.461 L 120.409 312.442 L 120.487 312.408 L 122.756 311.424 L 125.103 310.405 L 127.450 309.386 L 129.797 308.368 L 132.145 307.349 L 134.492 306.331 L 136.839 305.312 L 139.186 304.294 L 141.533 303.275 L 143.880 302.257 L 146.227 301.238 L 148.574 300.220 L 150.921 299.202 L 153.268 298.183 L 155.614 297.165 L 157.961 296.147 L 160.308 295.129 L 162.655 294.111 L 165.002 293.093 L 167.348 292.074 L 169.695 291.056 L 172.042 290.038 L 174.388 289.020 L 176.735 288.002 L 179.081 286.985 L 181.428 285.967 L 183.774 284.949 L 186.121 283.931 L 188.467 282.913 L 190.813 281.896 L 193.160 280.878 L 195.506 279.860 L 197.852 278.843 L 200.198 277.825 L 202.545 276.807 L 204.891 275.790 L 207.237 274.772 L 209.583 273.755 L 211.929 272.738 L 214.275 271.720 L 216.621 270.703 L 218.967 269.686 L 221.313 268.668 L 223.658 267.651 L 226.004 266.634 L 228.350 265.617 L 230.696 264.600 L 233.041 263.583 L 235.387 262.566 L 237.732 261.549 L 240.078 260.532 L 242.423 259.515 L 244.769 258.498 L 247.114 257.481 L 249.460 256.464 L 251.805 255.448 L 254.150 254.431 L 256.495 253.414 L 258.841 252.398 L 261.186 251.381 L 263.531 250.365 L 265.876 249.348 L 268.221 248.332 L 270.566 247.315 L 272.911 246.299 L 274.357 245.672 L 275.256 245.283 L 277.600 244.266 L 279.945 243.250 " fill="none" stroke="#24518a" stroke-width="1.4" stroke-dasharray="none" stroke-linecap="round"/><path class="transit-track-below-horizon" d="M 279.945 243.250 L 282.290 242.234 L 284.635 241.218 L 286.979 240.202 L 289.324 239.186 L 291.668 238.169 L 294.013 237.154 L 296.357 236.138 L 298.702 235.122 L 301.046 234.106 L 303.390 233.090 L 305.734 232.074 L 308.079 231.059 L 310.423 230.043 L 312.767 229.027 L 315.111 228.012 L 317.455 226.996 L 319.799 225.981 L 322.143 224.965 L 324.486 223.950 L 326.830 222.934 L 329.174 221.919 L 331.518 220.904 L 333.861 219.889 L 336.205 218.874 L 338.548 217.858 L 340.892 216.843 L 343.235 215.828 L 345.579 214.813 L 347.922 213.798 L 350.265 212.784 L 352.609 211.769 L 354.952 210.754 L 357.295 209.739 L 359.638 208.724 L 361.981 207.710 L 364.324 206.695 L 366.667 205.681 L 369.010 204.666 L 371.353 203.652 L 373.695 202.637 L 376.038 201.623 L 378.381 200.609 L 380.723 199.595 L 383.066 198.580 L 385.408 197.566 L 387.751 196.552 L 390.093 195.538 L 392.436 194.524 L 394.778 193.510 L 397.120 192.496 L 399.462 191.482 L 401.805 190.469 L 404.147 189.455 L 406.489 188.441 L 408.831 187.428 L 411.173 186.414 L 413.514 185.401 L 415.856 184.387 L 418.198 183.374 L 420.540 182.360 L 422.881 181.347 L 425.223 180.334 L 427.565 179.321 L 428.272 179.015 L 429.906 178.307 L 430.697 177.965 " fill="none" stroke="#8a8a8a" stroke-width="1.4" stroke-dasharray="5 4" stroke-linecap="round"/><circle class="transit-planet-c1" cx="118.061" cy="313.461" r="2.000" fill="#1d1d1d" fill-opacity="0.92" stroke="#000000" stroke-width="0.8"/><circLine truncated