Add comprehensive UI system with action bar, unit frame, and character sheet

- Created UI system in level/ui/ folder
  - Action bar with 12 ability slots (Attack, Block, Dash, Jump + 8 expansion slots)
  - Unit frame showing player portrait with health bar
  - Character sheet/spellbook (toggle with Tab) displaying stats, weapons, and abilities
  - Tab hint indicator showing how to open character sheet
  - Custom theme with golden borders and dark backgrounds

- UI Components:
  - HUD Manager autoload handles all UI initialization and player connections
  - Ability buttons with cooldown overlay and keybind display
  - Real-time health and cooldown tracking via signals
  - Scrollable character sheet with two-page layout

- Player Integration:
  - Added UI signals: dash_cooldown_updated, attack_cooldown_updated, weapon_equipped_changed
  - Mouse capture system (Escape to toggle, click to recapture)
  - Synced attack cooldown from weapons to player for UI tracking

- Updated level.gd to connect local player to HUD Manager
- Updated CLAUDE.md with git commit guidelines

level/ui/scripts/resource_bars.gd

@@ -0,0 +1,73 @@
+extends Control
+class_name ResourceBars
+## Resource bars (Health, Stamina, etc.) displayed above the action bar
+
+# Health bar references
+@onready var health_bg: ColorRect = $VBoxContainer/HealthBar/Background
+@onready var health_fill: ColorRect = $VBoxContainer/HealthBar/Background/Fill
+@onready var health_text: Label = $VBoxContainer/HealthBar/HealthText
+
+# Future: Stamina bar references
+# @onready var stamina_bg: ColorRect = $VBoxContainer/StaminaBar/Background
+# @onready var stamina_fill: ColorRect = $VBoxContainer/StaminaBar/Background/Fill
+
+# Player reference
+var player: Character = null
+
+# Smoothing
+var target_health_width: float = 0.0
+var current_health_width: float = 0.0
+const HEALTH_LERP_SPEED: float = 10.0
+
+# Colors
+const COLOR_HEALTH_HIGH = Color(0.0, 0.8, 0.0, 1.0)    # Green (>60%)
+const COLOR_HEALTH_MID = Color(1.0, 0.8, 0.0, 1.0)     # Yellow (30-60%)
+const COLOR_HEALTH_LOW = Color(0.8, 0.0, 0.0, 1.0)     # Red (<30%)
+
+func _ready():
+	# Initialize bars
+	if health_fill:
+		current_health_width = health_fill.size.x
+		target_health_width = health_fill.size.x
+
+	print("[ResourceBars] Resource bars initialized")
+
+func _process(delta):
+	# Smooth health bar animation
+	if health_fill and abs(current_health_width - target_health_width) > 0.1:
+		current_health_width = lerp(current_health_width, target_health_width, HEALTH_LERP_SPEED * delta)
+		health_fill.size.x = current_health_width
+
+## Set player reference
+func set_player(p: Character):
+	player = p
+	if player:
+		update_health(player.current_health, player.max_health)
+
+## Update health bar display
+func update_health(current: float, maximum: float):
+	if not health_fill or not health_bg or not health_text:
+		return
+
+	var health_percent = current / maximum if maximum > 0 else 0.0
+	health_percent = clamp(health_percent, 0.0, 1.0)
+
+	# Update fill width
+	var max_width = health_bg.size.x
+	target_health_width = max_width * health_percent
+
+	# Update color based on health percentage
+	if health_percent > 0.6:
+		health_fill.color = COLOR_HEALTH_HIGH
+	elif health_percent > 0.3:
+		health_fill.color = COLOR_HEALTH_MID
+	else:
+		health_fill.color = COLOR_HEALTH_LOW
+
+	# Update text
+	health_text.text = "%d / %d HP" % [int(current), int(maximum)]
+
+## Update stamina bar (for future use)
+func update_stamina(current: float, maximum: float):
+	# TODO: Implement when stamina system is added
+	pass