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/scenes/unit_frame.tscn

@@ -0,0 +1,93 @@
+[gd_scene load_steps=4 format=3 uid="uid://b7u8yhry4b74a"]
+
+[ext_resource type="Script" path="res://level/ui/scripts/unit_frame.gd" id="1_script"]
+[ext_resource type="Theme" uid="uid://dvsh7tuhulnfm" path="res://level/ui/theme/wow_style.tres" id="2_theme"]
+
+[sub_resource type="StyleBoxFlat" id="StyleBoxFlat_frame"]
+bg_color = Color(0.1, 0.1, 0.1, 0.85)
+border_width_left = 2
+border_width_top = 2
+border_width_right = 2
+border_width_bottom = 2
+border_color = Color(0.6, 0.5, 0.2, 1)
+corner_radius_top_left = 6
+corner_radius_top_right = 6
+corner_radius_bottom_right = 6
+corner_radius_bottom_left = 6
+
+[node name="UnitFrame" type="PanelContainer"]
+offset_left = 20.0
+offset_top = 20.0
+offset_right = 270.0
+offset_bottom = 120.0
+theme = ExtResource("2_theme")
+theme_override_styles/panel = SubResource("StyleBoxFlat_frame")
+script = ExtResource("1_script")
+
+[node name="MarginContainer" type="MarginContainer" parent="."]
+layout_mode = 2
+theme_override_constants/margin_left = 10
+theme_override_constants/margin_top = 10
+theme_override_constants/margin_right = 10
+theme_override_constants/margin_bottom = 10
+
+[node name="VBoxContainer" type="VBoxContainer" parent="MarginContainer"]
+layout_mode = 2
+theme_override_constants/separation = 6
+
+[node name="HBoxContainer" type="HBoxContainer" parent="MarginContainer/VBoxContainer"]
+layout_mode = 2
+
+[node name="LevelLabel" type="Label" parent="MarginContainer/VBoxContainer/HBoxContainer"]
+layout_mode = 2
+theme_override_colors/font_outline_color = Color(0, 0, 0, 1)
+theme_override_constants/outline_size = 2
+theme_override_font_sizes/font_size = 20
+text = "Lv 1"
+
+[node name="NameLabel" type="Label" parent="MarginContainer/VBoxContainer"]
+layout_mode = 2
+theme_override_colors/font_outline_color = Color(0, 0, 0, 1)
+theme_override_constants/outline_size = 2
+theme_override_font_sizes/font_size = 22
+text = "Player Name"
+
+[node name="HealthBarContainer" type="Control" parent="MarginContainer/VBoxContainer"]
+custom_minimum_size = Vector2(0, 30)
+layout_mode = 2
+
+[node name="Background" type="ColorRect" parent="MarginContainer/VBoxContainer/HealthBarContainer"]
+layout_mode = 1
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+grow_horizontal = 2
+grow_vertical = 2
+color = Color(0.2, 0.2, 0.2, 0.9)
+
+[node name="Fill" type="ColorRect" parent="MarginContainer/VBoxContainer/HealthBarContainer/Background"]
+layout_mode = 1
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+offset_left = 2.0
+offset_top = 2.0
+offset_right = -2.0
+offset_bottom = -2.0
+grow_horizontal = 2
+grow_vertical = 2
+color = Color(0, 0.8, 0, 1)
+
+[node name="HealthText" type="Label" parent="MarginContainer/VBoxContainer/HealthBarContainer"]
+layout_mode = 1
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+grow_horizontal = 2
+grow_vertical = 2
+theme_override_colors/font_outline_color = Color(0, 0, 0, 1)
+theme_override_constants/outline_size = 2
+theme_override_font_sizes/font_size = 16
+text = "100 / 100"
+horizontal_alignment = 1
+vertical_alignment = 1