Add game mode categories, character creation, on-foot ship/hub mode, RAM currency, and in-ship navigation

Bundles several sessions' worth of previously uncommitted work: map
categories with Domination/Conquest/King of the Hill mode stubs and a
server-list mode filter; a procedurally-drawn character-creation screen
replacing the old callsign-only PROFILE overlay; the on-foot groundwork
(walkable station hub, ship interior, character controller) plus the RAM
currency backend; and today's addition, an in-ship Helldivers-2-style
navigation table that QUICK PLAY's queue/connect flow and the Belters/
Military hub travel now live behind, with hub-and-ship return paths and a
context-aware pause menu usable both in-match and inside the ship.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

matchmaking-api/app/main.py

@@ -45,6 +45,8 @@ async def _seed_demo_servers() -> None:
                         status=ServerStatus.available,
                         player_count=player_count,
                         max_players=50,
+                        game_mode="team_deathmatch",
+                        map_name="Sector Alpha",
                     )
                 )
         await db.commit()