Initial commit: Transcience MVP

Top-down twin-stick bullet-hell, Godot 4.7, server-authoritative dedicated
server with client-side prediction. Clients send input only; the server
resolves every hit for both players and enemies (no PvP).

- SimWorld: whole simulation as plain RefCounted objects (no nodes, no
  physics server), ~0.24ms/tick at peak load -- runs headless for free and
  drives 78 tests in under a second
- BulletPool: struct-of-arrays bullet storage, replicated as spawn/despawn
  events rather than per-tick state
- Emitter framework (Ring/AimedSpread/WallGap/ArcSweep) shared by trash
  enemies and bosses -- a new boss is data in src/content/content.gd, no
  simulation changes
- The Warden of the Fold: stationary 4-phase boss built entirely on that
  format
- Lobby hub with a portal into on-demand dungeon instances; one process
  hosts the hub plus every concurrent dungeon
- Emergency escape: 3s server-owned channel, cancelled by damage
- tools/check.sh, test.sh (GUT), smoke.sh (real server + bot clients over
  ENet), bench.gd; git hooks wired to the same scripts
- docs/ARCHITECTURE.md, NETCODE.md, WORKFLOW.md, ROADMAP.md

src/core/game_opts.gd

@@ -0,0 +1,67 @@
+class_name GameOpts
+extends RefCounted
+## Process-wide options parsed from the command line.
+##
+## These are per-machine settings and must never affect the simulation -- if a
+## value would change how the world evolves, it belongs in [SimConfig] so server
+## and client cannot disagree about it.
+
+static var is_server: bool = false
+static var port: int = Protocol.DEFAULT_PORT
+static var host_address: String = "127.0.0.1"
+static var player_name: String = "player"
+## Replaces keyboard input with a scripted loop so CI can play the game with no
+## display. See `tools/smoke.sh`.
+static var bot_client: bool = false
+## Quit after this many physics ticks. 0 = run forever.
+static var autoquit_ticks: int = 0
+## Skip the menu and connect straight away. Implied by --bot.
+static var autojoin: bool = false
+## Skip the menu and start a listen server (host + local player).
+static var listen: bool = false
+## Server-side dev switch: new dungeons open straight onto the boss, skipping
+## the trash waves. For iterating on a pattern without clearing two waves first.
+static var boss_rush: bool = false
+static var parsed: bool = false
+
+
+static func parse(argv: PackedStringArray = PackedStringArray()) -> void:
+	if argv.is_empty():
+		argv = OS.get_cmdline_user_args()
+	var i := 0
+	while i < argv.size():
+		match argv[i]:
+			"--server":
+				is_server = true
+			"--bot":
+				bot_client = true
+				autojoin = true
+			"--join":
+				autojoin = true
+			"--listen":
+				listen = true
+			"--boss-rush":
+				boss_rush = true
+			"--port":
+				i += 1
+				if i < argv.size():
+					port = int(argv[i])
+			"--host":
+				i += 1
+				if i < argv.size():
+					host_address = argv[i]
+			"--name":
+				i += 1
+				if i < argv.size():
+					player_name = argv[i]
+			"--autoquit":
+				i += 1
+				if i < argv.size():
+					autoquit_ticks = int(argv[i])
+			"--verbose":
+				GameLog.min_level = GameLog.Level.DEBUG
+			"--quiet":
+				GameLog.min_level = GameLog.Level.WARN
+		i += 1
+	GameLog.role_tag = "server" if is_server else "client"
+	parsed = true