style(themes): align laptop/mobile keys + theme-coherent mobile accents

- Pad laptop:/mobile: to match each theme's existing key-column width
  (dark, light, custom were off by 1-4 spaces).
- Replace hardcoded #ec4899 mobile pink with palette-coherent accents:
  light  -> #db2777 (contrast on light bg)
  neon   -> #ff3399 (neon family)
  matrix -> #00cc66 (green palette)
  default/dark/custom keep #ec4899.

frontend/src/utils/themes.ts

@@ -183,7 +183,7 @@ export const THEMES: Record<ThemeId, ThemePreset> = {
         printer:       { border: '#6b7280', icon: '#6b7280' },
         computer:      { border: '#7c3aed', icon: '#7c3aed' },
         laptop:        { border: '#7c3aed', icon: '#7c3aed' },
-        mobile:       { border: '#ec4899', icon: '#ec4899' },
+        mobile:        { border: '#db2777', icon: '#db2777' },
         cpl:           { border: '#b45309', icon: '#b45309' },
         docker_host:       { border: '#2496ED', icon: '#2496ED' },
         docker_container:  { border: '#0369a1', icon: '#0369a1' },
@@ -246,7 +246,7 @@ export const THEMES: Record<ThemeId, ThemePreset> = {
         printer:      { border: '#8888ff', icon: '#8888ff' },
         computer:     { border: '#ff00ff', icon: '#ff00ff' },
         laptop:       { border: '#ff00ff', icon: '#ff00ff' },
-        mobile:       { border: '#ec4899', icon: '#ec4899' },
+        mobile:       { border: '#ff3399', icon: '#ff3399' },
         cpl:          { border: '#ffff00', icon: '#ffff00' },
         docker_host:       { border: '#00aaff', icon: '#00aaff' },
         docker_container:  { border: '#00ddff', icon: '#00ddff' },
@@ -309,7 +309,7 @@ export const THEMES: Record<ThemeId, ThemePreset> = {
         printer:      { border: '#005500', icon: '#005500' },
         computer:     { border: '#008822', icon: '#008822' },
         laptop:       { border: '#008822', icon: '#008822' },
-        mobile:       { border: '#ec4899', icon: '#ec4899' },
+        mobile:       { border: '#00cc66', icon: '#00cc66' },
         cpl:          { border: '#66ff33', icon: '#66ff33' },
         docker_host:       { border: '#00cc88', icon: '#00cc88' },
         docker_container:  { border: '#00aacc', icon: '#00aacc' },