Add ENet multiplayer (movement/combat sync) and matchmaking API

Networked play, end to end: connect, get matched, spawn, fight, respawn.

Godot side:
- Replace the single hardcoded Player with per-peer networked ships
  (MultiplayerSpawner + custom spawn_function), driven by client-side
  prediction with server reconciliation for movement.
- Server-authoritative combat: bullets, health, death/respawn all decided
  by the server and broadcast to every peer over RPC.
- Fix a Camera2D bug where Godot auto-promotes the first camera to ever
  enter the scene tree as the active one regardless of its own `current`
  value — with MultiplayerSpawner catch-up replication that was almost
  never the local player's own ship. `make_current()` on the owner's
  camera fixes it; property assignment doesn't reliably override the
  auto-claim.
- Fix two "late joiner never learns already-established state" gaps
  (health, visibility) by folding both into the existing per-tick
  position broadcast instead of relying on one-shot RPCs that only reach
  peers already connected when they fire.
- Make the 2 offered factions in team select match for every player in
  a match: the server decides once and clients either read it directly
  (server's own instance) or request it over RPC, rather than each
  client rolling its own random pair.
- New MatchmakingClient autoload wires the main menu's CASUAL/RANKED
  buttons to the matchmaking API instead of connecting directly.

New matchmaking-api/ (FastAPI + Postgres, Docker Compose):
- Queue/match/stats/ranks endpoints. In-memory matchmaking queue in a
  single API process — no Redis until there's an actual reason to shard
  the queue across instances.
- Background loop forms a match once enough players are queued for a
  mode, assigns the first available registered game server.
- No real server pool yet: one dev server is auto-seeded from
  DEV_SEED_SERVER_IP/PORT; POST /servers/register exists for real
  servers to self-register later but nothing calls it yet.

Docs: CLAUDE.md and overview/tech.md updated to match — networking
checklist mostly checked off, matchmaking backend section rewritten to
describe what was actually built vs. the original Go/Redis plan, and
Current Tasks reordered around what's actually left (bot fill, real
server pool, ranked/MMR refinement, lag compensation).

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

spacewar/menu/team_select.gd

@@ -1,4 +1,5 @@
 extends CanvasLayer
+class_name TeamSelect
 
 # Movement speed factor by role, shared across all 3 races so e.g. every
 # race's Interceptor moves at the same speed as every other race's.
@@ -116,21 +117,41 @@ const ROW_IMG   := 95.0
 
 var _root: Control
 var _content: Control
+var _loading_lbl: Label
 var _offered: Array = []
 var _chosen_race: Dictionary = {}
 
 
 func _ready() -> void:
 	layer = 20
-	_offered = _pick_two_races()
 	_build_root()
+
+	# The 2 offered races must be the same for every player in the match, not
+	# independently randomized per client — the server decides once (see
+	# World.decide_offered_races()) and every client either asks for it
+	# (real remote peers) or reads it directly (the server's own instance,
+	# no round-trip needed since it's the same process).
+	var world := get_node("/root/World")
+	if multiplayer.is_server():
+		offer_races(world.decide_offered_races())
+	else:
+		world.request_offered_races.rpc_id(1)
+
+
+# Called once this client knows which 2 races (by id) the match is offering.
+func offer_races(race_ids: Array) -> void:
+	if _loading_lbl:
+		_loading_lbl.queue_free()
+		_loading_lbl = null
+	_offered = race_ids.map(func(id): return _race_by_id(id))
 	_show_race_selection()
 
 
-func _pick_two_races() -> Array:
-	var pool := RACES.duplicate()
-	pool.shuffle()
-	return [pool[0], pool[1]]
+func _race_by_id(id: int) -> Dictionary:
+	for race in RACES:
+		if race.id == id:
+			return race
+	return RACES[0]
 
 
 func _build_root() -> void:
@@ -144,6 +165,9 @@ func _build_root() -> void:
 	overlay.mouse_filter = Control.MOUSE_FILTER_STOP
 	_root.add_child(overlay)
 
+	_loading_lbl = _label(_root, "LOADING MATCH...", 20, Color(0.5, 0.6, 0.75),
+		0, 380, 1280, 420, HORIZONTAL_ALIGNMENT_CENTER)
+
 
 func _swap_content() -> Control:
 	if _content:
@@ -179,7 +203,6 @@ func _show_race_selection() -> void:
 
 func _on_race_chosen(race: Dictionary) -> void:
 	_chosen_race = race
-	GameConfig.player_race = race.id
 	_show_ship_selection()
 
 
@@ -203,10 +226,9 @@ func _show_ship_selection() -> void:
 
 
 func _on_ship_chosen(ship: Dictionary) -> void:
-	GameConfig.player_ship_path = ship.path
-	GameConfig.player_ship_scale = ship.scale
-	GameConfig.player_ship_speed_factor = ship.speed_factor
-	GameConfig.team_selected.emit()
+	PlayerRegistry.submit_local_loadout(
+		GameConfig.player_name, _chosen_race.id, ship.path, ship.scale, ship.speed_factor
+	)
 	queue_free()
 
 
@@ -346,7 +368,7 @@ func _make_ship_row(ship: Dictionary, accent: Color) -> Button:
 
 func _label(parent: Control, text: String, font_size: int, color: Color,
 		x1: float, y1: float, x2: float, y2: float,
-		align: HorizontalAlignment = HORIZONTAL_ALIGNMENT_LEFT) -> void:
+		align: HorizontalAlignment = HORIZONTAL_ALIGNMENT_LEFT) -> Label:
 	var lbl := Label.new()
 	lbl.text = text
 	lbl.horizontal_alignment = align
@@ -355,6 +377,7 @@ func _label(parent: Control, text: String, font_size: int, color: Color,
 	lbl.add_theme_color_override("font_color", color)
 	_place(lbl, x1, y1, x2, y2)
 	parent.add_child(lbl)
+	return lbl
 
 
 func _place(node: Control, x1: float, y1: float, x2: float, y2: float) -> void: