Add automated test framework and 21 regression tests

- tests/runner.gd: lightweight headless test runner (TAP format output)
- tests/weapons.gd: 6 tests for weapon registry and stats
- tests/team.gd: 5 tests for team assignment and balancing
- tests/economy.gd: 6 tests for economy constants and loss streaks
- tests/bootstrapper.gd: 4 tests for LAN bootstrapper input parsing

Run with: godot --headless -s tests/runner.gd --path .

All 21 tests pass on Linux and Windows.

tests/weapons.gd

@@ -0,0 +1,76 @@
+extends RefCounted
+
+## Weapon registry tests — no framework dependencies, no class_name types.
+## Each test_* method returns "" on pass or an error message on fail.
+##
+## Uses direct integer enum values to avoid class_name loading order issues:
+##   FireMode: SEMI=0, AUTO=1, MELEE=2
+
+const Registry := preload("res://examples/multiplayer-fps/scripts/data/weapon_registry.gd")
+
+const KNIFE := 1
+const GLOCK := 2
+const USP   := 3
+const AK47  := 4
+const M4A1  := 5
+const AWP   := 6
+
+func _check_field(w, field: String, expected) -> String:
+	var actual = w.get(field)
+	if actual != expected:
+		return "  %s: got %s, expected %s" % [field, str(actual), str(expected)]
+	return ""
+
+func test_all_weapons_registered() -> String:
+	var ids := [KNIFE, GLOCK, USP, AK47, M4A1, AWP]
+	for id in ids:
+		var w := Registry.get_weapon(id)
+		if w == null:
+			return "Weapon ID %d not registered" % id
+	return ""
+
+func test_unknown_id_returns_null() -> String:
+	if Registry.get_weapon(0) != null:  return "ID 0 should return null"
+	if Registry.get_weapon(99) != null: return "ID 99 should return null"
+	if Registry.get_weapon(-1) != null: return "ID -1 should return null"
+	return ""
+
+func test_ak47_stats() -> String:
+	var w := Registry.get_weapon(AK47)
+	if w == null:  return "AK47 not found"
+	var e := ""
+	e += _check_field(w, "weapon_name", "AK-47")
+	e += _check_field(w, "damage", 36)
+	e += _check_field(w, "fire_mode", 1)  # AUTO=1
+	e += _check_field(w, "team", 0)       # T=0
+	e += _check_field(w, "price", 2500)
+	e += _check_field(w, "slot", 2)
+	return e
+
+func test_awp_stats() -> String:
+	var w := Registry.get_weapon(AWP)
+	if w == null:  return "AWP not found"
+	var e := ""
+	e += _check_field(w, "weapon_name", "AWP")
+	e += _check_field(w, "damage", 110)
+	e += _check_field(w, "fire_mode", 0)  # SEMI=0
+	e += _check_field(w, "price", 4750)
+	return e
+
+func test_knife_stats() -> String:
+	var w := Registry.get_weapon(KNIFE)
+	if w == null:  return "Knife not found"
+	var e := ""
+	e += _check_field(w, "weapon_name", "Knife")
+	e += _check_field(w, "damage", 50)
+	e += _check_field(w, "fire_mode", 2)  # MELEE=2
+	e += _check_field(w, "price", 0)
+	return e
+
+func test_default_pistol() -> String:
+	var e := ""
+	var t := Registry.get_default_pistol(0)
+	if t != GLOCK:  e += "  T side should get Glock, got %d" % t
+	var ct := Registry.get_default_pistol(1)
+	if ct != USP:   e += "  CT side should get USP, got %d" % ct
+	return e