Add blood decals, gore, mobile HUD, web start gate + touch/perf tests

Remove tools/fstest.html scratch page used to probe browser
fullscreen/orientation APIs.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EznnY8rH2dXhtono1kwsXg

debug_params.gd

@@ -306,6 +306,18 @@ func _register_all() -> void:
 	# it), so it can't be perma-stunlocked — it gets a window to commit an attack that then
 	# rides its hyper-armour. 0 = no poise (stun-locks under sustained fire).
 	_reg_f("Bear",     "bear_stagger_cd",      1.0,  0.0,   4.0, 0.05)
+	# ── Blood ─────────────────────────────────────────────────────────────────
+	# Persistent floor/wall splats (blood_decals.gd), fired via the Gore autoload and
+	# gated by the player's Settings.gore. blood_cap is the ring-buffer size: past it,
+	# new splats overwrite the oldest so fill/memory stay bounded. blood_scale is a
+	# global size multiplier over each hit's own size; satellites are extra droplets
+	# scattered per floor cluster; the wall fan casts blood_wall_rays outward and stains
+	# any wall within blood_wall_reach metres of the hit.
+	_reg_f("Blood",    "blood_cap",          192.0,  0.0, 512.0, 16.0)
+	_reg_f("Blood",    "blood_scale",          1.0,  0.1,   4.0, 0.05)
+	_reg_f("Blood",    "blood_satellites",     3.0,  0.0,   8.0, 1.0)
+	_reg_f("Blood",    "blood_wall_reach",     2.5,  0.0,   6.0, 0.1)
+	_reg_f("Blood",    "blood_wall_rays",      8.0,  0.0,  16.0, 1.0)
 	# ── Sword ─────────────────────────────────────────────────────────────────
 	# Local seating of the sword in the right hand (drawn / fighting).
 	# The blade model runs along its local +Z, but weapon_bone (like every rig bone)
@@ -422,6 +434,14 @@ func _register_all() -> void:
 	# On-screen readout of live touch state (event count, last position, active zone) so
 	# touch problems can be diagnosed on the actual device, where no console is reachable.
 	_reg_b("Touch",    "touch_debug",          false)
+	# Rebuild skinned characters as rigid, bone-attached mesh pieces instead of GPU vertex
+	# skinning. This was a workaround for older Mali/ANGLE web GPUs where Compatibility skinning
+	# rendered characters invisible — but the Godot 4.7 web templates fixed that (confirmed
+	# on-device), so native skinning is now the default everywhere: it renders the bear's dense
+	# mesh without the rigid-seam holes AND drops the per-spawn SurfaceTool rebuild that was
+	# spiking the arena on matador spawn. Kept as an opt-in fallback (DP toggle, or ?skin=1 in
+	# the URL) in case a device is found where Compatibility skinning still fails.
+	_reg_b("Render",   "use_rigid_skin",       false)
 
 
 func _reg_f(section: String, key: String, default: float,