Added dark mode support with theme persistence. The theme selection is saved to localStorage so it persists across sessions. The toggle is in the new settings page along with other configuration options.

Built out several new views. The Markets component displays market data from all known locations with pricing information. AvailableShips shows ships that can be purchased with their prices and locations. The Settings page centralizes configuration options.

Added filtering to the trades view so you can narrow down by good type, ship, or location. Also improved the net worth calculation display with better breakdown of assets.

Various UI polish including tooltips on icons and setting a proper default route.