feat: implement weapon set system (t_p2_weapons)

- WeaponData resource class with configurable weapon properties and
  pre-configured constants for rifle, pistol, shotgun, and SMG
- WeaponDefinitions singleton/static registry with WEAPONS dictionary
- WeaponServer node for server-authoritative weapon logic including
  fire rate cooldowns, ammo tracking, reload state machine, and
  multi-pellet hit-scan raycasting
- Extended WeaponManager with weapon inventory array, weapon switching,
  per-weapon state persistence, fire_animation_triggered signal

scripts/combat/weapon_data.gd

@@ -0,0 +1,105 @@
+## WeaponData — A resource defining a weapon's static properties.
+##
+## Used as the data contract between weapon_definitions.gd, weapon_server.gd,
+## and weapon_manager.gd. Each weapon type is pre-configured and accessible
+## via the class-level constants (RIFLE, PISTOL, SHOTGUN, SMG).
+##
+## Usage:
+##   var data: WeaponData = WeaponData.RIFLE
+##   print(data.display_name)  # "Assault Rifle"
+##
+extends Resource
+class_name WeaponData
+
+# ---------------------------------------------------------------------------
+# Properties
+# ---------------------------------------------------------------------------
+
+## Unique identifier string (e.g., "rifle", "pistol").
+@export var weapon_id: String = ""
+
+## Human-readable weapon name.
+@export var display_name: String = ""
+
+## Base damage per projectile/pellet.
+@export var damage: float = 0.0
+
+## Rate of fire in rounds per second (Hz).
+@export var fire_rate: float = 0.0
+
+## Magazine capacity (max ammo per reload).
+@export var mag_size: int = 0
+
+## Reload duration in seconds.
+@export var reload_time: float = 0.0
+
+## If true, hold to fire continuously. If false, single-shot per press.
+@export var is_automatic: bool = false
+
+## Base weapon spread in degrees (used for accuracy cone).
+@export var spread_degrees: float = 0.0
+
+## Effective range in Godot units (metres conceptual).
+@export var range: float = 0.0
+
+## Number of pellets/projectiles per shot (1 for most weapons, 8 for shotgun).
+@export var pellets_per_shot: int = 1
+
+# ---------------------------------------------------------------------------
+# Pre-configured weapon instances (class-level constants)
+# ---------------------------------------------------------------------------
+
+## Assault Rifle — 30 dmg, 10 rps, 30 mag, 2.1s reload, automatic, 0.5° spread, 200m range.
+const RIFLE: Resource = pref(
+    "rifle", "Assault Rifle",
+    30.0, 10.0, 30, 2.1, true, 0.5, 200.0, 1
+)
+
+## Pistol — 25 dmg, 4 rps, 12 mag, 1.5s reload, semi-auto, 0.3° spread, 80m range.
+const PISTOL: Resource = pref(
+    "pistol", "Pistol",
+    25.0, 4.0, 12, 1.5, false, 0.3, 80.0, 1
+)
+
+## Shotgun — 8 dmg × 8 pellets, 1 rps, 8 mag, 3.0s reload, semi-auto, 3° spread, 30m range.
+const SHOTGUN: Resource = pref(
+    "shotgun", "Shotgun",
+    8.0, 1.0, 8, 3.0, false, 3.0, 30.0, 8
+)
+
+## SMG — 18 dmg, 12 rps, 25 mag, 1.8s reload, automatic, 1.5° spread, 100m range.
+const SMG: Resource = pref(
+    "smg", "Submachine Gun",
+    18.0, 12.0, 25, 1.8, true, 1.5, 100.0, 1
+)
+
+# ---------------------------------------------------------------------------
+# Factory helper
+# ---------------------------------------------------------------------------
+
+## Internal helper that constructs a WeaponData instance from raw values.
+## This avoids repeating the constructor boilerplate for every constant.
+static func pref(
+    _weapon_id: String,
+    _display_name: String,
+    _damage: float,
+    _fire_rate: float,
+    _mag_size: int,
+    _reload_time: float,
+    _is_automatic: bool,
+    _spread_degrees: float,
+    _range: float,
+    _pellets: int = 1
+) -> WeaponData:
+    var w := WeaponData.new()
+    w.weapon_id = _weapon_id
+    w.display_name = _display_name
+    w.damage = _damage
+    w.fire_rate = _fire_rate
+    w.mag_size = _mag_size
+    w.reload_time = _reload_time
+    w.is_automatic = _is_automatic
+    w.spread_degrees = _spread_degrees
+    w.range = _range
+    w.pellets_per_shot = _pellets
+    return w