Add capital ships, and settings screen with smooth-motion fixes

Capital ships & support art:
- New Flagship capital ships (world/flagship.gd) spawn a small
  point-defense formation at each team's spawn marker, independently
  targeting the nearest enemy in range with a slow unmissable-looking
  missile and a faster bullet stream -- keeps a team from parking on
  the enemy spawn and farming respawns.
- Per-race/role bullet sprites for turret fire (assets/images/effects/
  bullets/), flagship art for both factions, minimap now draws
  flagship blips, bot_ai awareness tuned to notice them.

Settings screen (items 20-21 in CLAUDE.md) -- was a stub, now five
real sections shared between the main menu and the in-game pause menu:
- Diagnosed and fixed a "movement looks blurry/laggy" report down to
  three independent causes: physics-tick vs. display-refresh judder
  (fixed via Godot's built-in physics interpolation, plus a
  frame-rate-cap + VSync dropdown so each player can match their own
  monitor), missing mipmaps on every minified ship texture (real GPU
  sampling shimmer, unrelated to frame timing), and a periodic hitch
  from the matchmaking heartbeat spinning up a new HTTPRequest thread
  every 8 seconds instead of reusing one.
- Nameplates get their own manual per-frame interpolation, since
  Godot's physics interpolation only covers Node2D/Node3D, not the
  Control-based Label they're built from.
- Audio: Master/Music/SFX volume sliders backed by a real bus layout
  (default_bus_layout.tres) -- the project had no volume control at
  all before this.
- Window mode (Fullscreen/Exclusive Fullscreen/Windowed), a
  colorblind-friendly enemy-color toggle (also fixes the minimap's own
  separate, inconsistent yellow enemy color), and keyboard rebinding
  for every action with a live capture UI.
- New GameConfig.settings_focused flag (same pattern as chat_focused/
  team_select_focused) so a key-rebind capture can't also move the
  ship or toggle the pause menu underneath the panel.

Spawn intro: a ship's first-ever appearance now eases in from a
random direction (fast off the start, decelerating into its landing
spot) instead of popping into place -- purely a cosmetic sprite
offset, so collision/camera/networking are untouched and every peer
(including bots) sees the same warp-in.

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

spacewar/menu/team_select.gd

@@ -13,6 +13,7 @@ const RACES := [
 	{
 		"id": 1, "name": "INNER SPHERE NAVY", "sub": "Gunmetal-gray navy of Earth, Mars, and Mercury — disciplined, frontal, built to hold a line",
 		"color": Color(0.80, 0.32, 0.32),
+		"flagship_path": "res://assets/images/ships/isn/flagship_colossus.png", "flagship_scale": 1.0,
 		"ships": [
 			{
 				"name": "PATRIOT", "role": "Fighter",
@@ -40,6 +41,7 @@ const RACES := [
 	{
 		"id": 2, "name": "OUTER RIM COLLECTIVE", "sub": "Gritty, jury-rigged mining rebels — kinetic weapons scavenged and welded onto anything that flies",
 		"color": Color(0.82, 0.52, 0.24),
+		"flagship_path": "res://assets/images/ships/orc/flagship_rust_titan.png", "flagship_scale": 1.0,
 		"ships": [
 			{
 				"name": "RAIL-JACK", "role": "Fighter",