feat(earth): toolbar and zoom improvements

- Add box-sizing/padding normalization to toolbar buttons
- Remove zoom slider, implement click/hold zoom behavior (+/- buttons)
- Add 10% step on click, 1% continuous on hold
- Fix satellite init: show satellite points immediately, delay trail visibility
- Fix breathing effect: faster pulse, wider opacity range
- Add toggle-cables functionality with visibility state
- Initialize satellites and cables as visible by default

frontend/public/earth/js/constants.js

@@ -39,11 +39,11 @@ export const CABLE_COLORS = {
 };
 
 export const CABLE_CONFIG = {
-  lockedOpacityMin: 0.6,
+  lockedOpacityMin: 0.2,
   lockedOpacityMax: 1.0,
   otherOpacity: 0.5,
   otherBrightness: 0.6,
-  pulseSpeed: 0.003,
+  pulseSpeed: 0.008,
   pulseCoefficient: 0.4
 };