feat: add satellite selection plugin for TOCA/POCA analysis

Create a new plugin that allows users to select a primary satellite and a target
satellite to compute the Time of Closest Approach (TOCA) and Point of Closest
Approach (POCA) between them.

Features:
- Propagates both satellites' ECI positions using SGP4
- Calculates distance between satellites at each time step
- Identifies local minima in distance to find closest approaches
- Displays next 10 TOCAs and POCAs in a side menu
- Clicking on an entry changes simulation time to that event
- Highlights both satellites in the search bar when an event is clicked
- Side menu styled similar to collisions plugin
- 7-day lookahead with 60-second time steps

Files added:
- src/plugins/satellite-selection/satellite-selection.ts
- src/plugins/satellite-selection/satellite-selection.css
- public/img/icons/satellite-selection.png

Files modified:
- src/plugins/plugins.ts (plugin registration)
- src/plugins/keeptrack-plugins-configuration.ts (plugin configuration)

Author: claude

public/img/icons/satellite-selection.png

@@ -62,6 +62,7 @@ export type KeepTrackPluginsConfiguration = {
   NextLaunchesPlugin?: PluginConfiguration;
   OrbitReferences?: PluginConfiguration;
   SatellitePhotos?: PluginConfiguration;
+  SatelliteSelection?: PluginConfiguration;
   Planetarium?: PluginConfiguration;
   EciPlot?: PluginConfiguration;
   EcfPlot?: PluginConfiguration;

src/plugins/keeptrack-plugins-configuration.ts

@@ -55,6 +55,7 @@ import { SatInfoBoxSensor } from './sat-info-box-sensor/sat-info-box-sensor';
 import { SatInfoBox } from './sat-info-box/sat-info-box';
 import { SatelliteFov } from './satellite-fov/satellite-fov';
 import { SatellitePhotos } from './satellite-photos/satellite-photos';
+import { SatelliteSelection } from './satellite-selection/satellite-selection';
 import { ScenarioManagementPlugin } from './scenario-management/scenario-management';
 import { ScreenRecorder } from './screen-recorder/screen-recorder';
 import { Screenshot } from './screenshot/screenshot';
@@ -187,6 +188,7 @@ export class PluginManager {
         { init: () => new ProximityOps().init(), config: plugins.ProximityOps },
         { init: () => new OrbitReferences().init(), config: plugins.OrbitReferences },
         { init: () => new Collisions().init(), config: plugins.Collisions },
+        { init: () => new SatelliteSelection().init(), config: plugins.SatelliteSelection },
         { init: () => new OrbitGuardMenuPlugin().init(), config: plugins.OrbitGuardMenuPlugin },
         { init: () => new TrackingImpactPredict().init(), config: plugins.TrackingImpactPredict },
         { init: () => new Breakup().init(), config: plugins.Breakup },

src/plugins/plugins.ts

@@ -0,0 +1,60 @@
+/**
+ * Styling for the Satellite Selection (TOCA/POCA) Plugin
+ */
+
+#SatelliteSelection-menu {
+  min-width: 600px;
+}
+
+#SatelliteSelection-table {
+  line-height: 1.5;
+  font-size: 14px;
+  margin-top: 15px;
+  margin-bottom: 20px;
+  width: 100%;
+}
+
+#SatelliteSelection-table td {
+  text-align: center;
+  padding: 8px 5px;
+}
+
+#SatelliteSelection-table th {
+  text-align: center;
+  padding: 8px 5px;
+}
+
+#SatelliteSelection-satellite-info {
+  margin-bottom: 15px;
+  padding: 10px;
+  background-color: rgba(0, 0, 0, 0.1);
+  border-radius: 5px;
+}
+
+#SatelliteSelection-satellite-info p {
+  margin: 5px 0;
+  font-weight: bold;
+  font-size: 14px;
+}
+
+#SatelliteSelection-primary-sat {
+  color: #4CAF50;
+}
+
+#SatelliteSelection-target-sat {
+  color: #2196F3;
+}
+
+#SatelliteSelection-set-target-btn {
+  margin-top: 10px;
+  margin-bottom: 15px;
+}
+
+.SatelliteSelection-event {
+  cursor: pointer;
+  transition: background-color 0.2s ease;
+}
+
+.SatelliteSelection-event:hover {
+  background-color: rgba(255, 255, 255, 0.1);
+}