Wire up UI in Godot 4: fonts, translations, layout, fog, shadow

Discovered while playtesting the migrated build. Each fix has a
specific Godot-3-to-4 cause that the --convert-3to4 tool did not catch.

Fonts:
- Replace 4 .tres font wrappers (MKX_Base, kirsty_base/medium/title)
  with FontVariation pointing at the .otf/.ttf source. Godot 3
  DynamicFont with size= and font_data= is invalid in Godot 4 (those
  properties don't exist on FontFile).
- Apply size 46 via theme_override_font_sizes/font_size on the 5
  Labels that used kirsty_title.tres (LabelLoading + 4 in Summary).
- Drop the broken VisualShader text_outline.material from the 4
  Labels in Summary — Index p_from_port errors in Godot 4 meant
  COLOR was never written, so text rendered invisible.
- Migrate VisualShader nodes inside text_outline.material (compressed
  asset; updated by the inspect/migrate scripts).

Translations:
- Move project.godot section from [locale] (Godot 3) to
  [internationalization] with locale/translations=... (Godot 4). The
  old section was silently ignored so tr() returned the raw msgid.
- Adjust Setting.translate_int_to_locale to return "en"/"fr" to
  match what the .po files declare (was "en_GB"/"fr_FR", which Godot
  3 fell back from automatically but Godot 4 does not).

Label alignment (Godot 3 names not auto-renamed):
- align -> horizontal_alignment, valign -> vertical_alignment across
  9 .tscn files.

Background / Loading / ChooseScene layout:
- Rewrite Background.tscn from a VisualShader-textured Panel to a
  plain TextureRect (the visual shader connection ports went out of
  bounds in Godot 4, leaving the panel grey on scene reload).
- Set layout_mode=1 + anchors_preset=15 on BackgroundPicture
  instances in Main.tscn and Loading.tscn — Godot 4 inheritance no
  longer applies the .tscn-root's anchors to an instanced child
  unless layout_mode is set to Anchors mode explicitly.
- Replace scroll_horizontal_enabled (Godot 3) with
  horizontal_scroll_mode/vertical_scroll_mode (Godot 4) on
  ChooseScene's ScrollContainer.
- Add theme_override_styles/panel = StyleBoxEmpty on the
  ScrollContainer (Godot 4 ScrollContainer ships a default dark
  panel style that Godot 3 did not).
- Hide BackgroundTile in Template.tscn — it points at
  UI-level-btn-shadow.png (228x228, 83% opaque black) which used to
  render at natural size in Godot 3 but is stretched to fill the
  456px rect in Godot 4, leaving a big black square below each
  thumbnail. The proper drop-shadow needs a shader or 9-patch.
- TextureRect.expand=true (Godot 3) -> expand_mode=1 (Godot 4) on
  ThumbnailLevel and TopPart's content rects.

Lighting:
- background_mode 3 (which used to mean Sky in Godot 3) -> 2 (Sky in
  Godot 4; 3 is now Canvas, producing a black background).
- background_sky -> sky, background_energy -> background_energy_multiplier,
  fog_color -> fog_light_color, fog_height_min -> fog_height; drop
  fog_height_enabled / fog_height_max / fog_height_curve /
  dof_blur_far_distance (no longer exist).
- Add fog_mode = 1 so Godot 4 uses fog_depth_* instead of the new
  default fog_density-based exponential fog (which rendered as a
  thick white cloud).
- ambient_light_energy 1.55 -> 0.4 — the new pipeline interprets
  the value much more strongly so 1.55 produced a saturated pink scene.
- Remove the light_data = ExtResource(41) reference to
  WarCraft.lmbake — Godot 3 baked lightmap binary format is
  incompatible with Godot 4. Re-bake in editor when ready.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scenes/UI/background/Background.tscn

@@ -1,62 +1,10 @@
-[gd_scene load_steps=7 format=2]
+[gd_scene load_steps=2 format=3]
 
-[ext_resource path="res://assets/ui/themes/bck.jpg" type="Texture2D" id=1]
+[ext_resource type="Texture2D" path="res://assets/ui/themes/bck.jpg" id="1"]
 
-[sub_resource type="VisualShaderNodeInput" id=1]
-input_name = "screen_uv"
-
-[sub_resource type="VisualShaderNodeTexture" id=2]
-texture = ExtResource( 1 )
-texture_type = 1
-
-[sub_resource type="VisualShaderNodeInput" id=3]
-input_name = "screen_texture"
-
-[sub_resource type="VisualShader" id=4]
-code = "shader_type canvas_item;
-uniform sampler2D tex_frg_4 : source_color;
-
-
-
-void vertex() {
-// Output:0
-
-}
-
-void fragment() {
-// Texture:4
-	vec4 tex_frg_4_read = texture(tex_frg_4, UV.xy);
-	vec3 n_out4p0 = tex_frg_4_read.rgb;
-	float n_out4p1 = tex_frg_4_read.a;
-
-// Output:0
-	COLOR.rgb = n_out4p0;
-
-}
-
-void light() {
-// Output:0
-
-}
-"
-graph_offset = Vector2( -1049.92, -300 )
-mode = 1
-flags/light_only = false
-nodes/fragment/3/node = SubResource( 1 )
-nodes/fragment/3/position = Vector2( -840, 460 )
-nodes/fragment/4/node = SubResource( 2 )
-nodes/fragment/4/position = Vector2( -80, 60 )
-nodes/fragment/5/node = SubResource( 3 )
-nodes/fragment/5/position = Vector2( -1000, 20 )
-nodes/fragment/connections = PackedInt32Array( 4, 0, 0, 0 )
-
-[sub_resource type="ShaderMaterial" id=5]
-shader = SubResource( 4 )
-
-[node name="BackgroundPicture" type="Panel"]
-material = SubResource( 5 )
+[node name="BackgroundPicture" type="TextureRect"]
 anchor_right = 1.0
 anchor_bottom = 1.0
-__meta__ = {
-"_edit_use_anchors_": false
-}
+texture = ExtResource("1")
+expand_mode = 1
+stretch_mode = 6