feat: cel-shaded look & feel overhaul — real audio, comic UI, themed VFX

Audio (all CC0 — Kenney packs + OpenGameArt, see assets/sounds/SOURCES.md):
- Replace every procedural synth WAV with forged sounds (ffmpeg pitch/layer
  mixes): distinct fire sounds per weapon with 2-3 variations, explosions,
  footsteps x5, land/jump/dash/vault, knife swing, hit/kill confirms,
  bullet impacts, reload, flight loops, UI hover/click/confirm/error,
  match jingles, menu music
- AudioManager.stream_for(): AudioStreamRandomizer per sound id — every
  weapon now gets variation + pitch randomization on each shot
- Explosions and bullet impacts play positional audio; landing has its own
  sound instead of a pitched footstep; ambient wind bed on every map

Visuals:
- ExplosionVFX: shared cel-shaded burst (white-hot stepped core, ink
  shockwave ring, star spikes, flat smoke puffs) replaces the orange
  sphere in both local and remote-replay paths
- Comic star muzzle flashes on all weapons; unified cel tracer bolts with
  ink outlines across hitscan/shotgun/remote paths
- Impact decals: hard-stepped ink-splat gradients instead of soft airbrush
- Toon shading on first-person view models + arms, third-person weapons,
  and the procedural humanoid fallback (no hull outlines on FBX weapons —
  their hard normals tear the inverted hull)
- Fix: giant soft "blob" highlight on floors — toon rim/specular disabled
  on level-geometry materials (pre-existing artifact since the cel commit)
- Fix: own third-person weapon rendered into the first-person camera
  (shadows-only now covers first_person_mode)

UI:
- UITheme: comic theme on the root window — Bangers display font (OFL),
  paper panels with thick ink borders + hard drop shadows, papaya accent,
  themed buttons/inputs/popups; hover/click sounds on all menu buttons
- Main menu: tilted comic wordmark, sunset toon diorama, looping menu music
- Match HUD: themed scoreboard/killfeed/kill counter

Viewports:
- 4x MSAA project-wide + viewmodel/diorama viewports (crisp ink lines)
- Viewmodel camera near plane 0.01; third-person camera FOV syncs settings
- debug/visual_capture.gd: dev tool to screenshot menu + level for review

Verified: 11/11 movement tests, spawn smoke test 0 failures, before/after
screenshot comparison of menu and level.

Co-Authored-By: Claude Fable 5 <[email protected]>

ui/match_hud.gd

@@ -16,7 +16,10 @@ var _scoreboard_grid: GridContainer
 
 func _ready() -> void:
 	_nm = get_node_or_null("/root/NetworkManager")
-	
+	# Ensure the comic theme is active even when a level is loaded directly
+	# (tests, debug runs) without passing through the main menu.
+	UITheme.apply_global(get_tree())
+
 	# Top HUD
 	var top_hbox = HBoxContainer.new()
 	top_hbox.set_anchors_preset(Control.PRESET_TOP_WIDE)
@@ -37,8 +40,8 @@ func _ready() -> void:
 	_local_kills_label = Label.new()
 	_local_kills_label.text = "0 Kills"
 	_local_kills_label.add_theme_font_size_override("font_size", 64)
-	_local_kills_label.add_theme_color_override("font_color", Color(1, 0.8, 0.2))
-	_local_kills_label.add_theme_color_override("font_outline_color", Color.BLACK)
+	_local_kills_label.add_theme_color_override("font_color", UITheme.PAPAYA)
+	_local_kills_label.add_theme_color_override("font_outline_color", UITheme.INK)
 	_local_kills_label.add_theme_constant_override("outline_size", 12)
 	top_hbox.add_child(_local_kills_label)
 	
@@ -68,9 +71,7 @@ func _ready() -> void:
 	
 	_scoreboard_panel = PanelContainer.new()
 	_scoreboard_panel.custom_minimum_size = Vector2(800, 600)
-	var sb_style = StyleBoxFlat.new()
-	sb_style.bg_color = Color(0, 0, 0, 0.8)
-	_scoreboard_panel.add_theme_stylebox_override("panel", sb_style)
+	# Styled by the shared UITheme PanelContainer stylebox (ink-border card)
 	_scoreboard_panel.hide()
 	center_container.add_child(_scoreboard_panel)