Rename to Work-Death Balance, add mascot favicon and rebalance rifle/grenade damage

docs/GAMEPLAY-IMPROVEMENTS.md

@@ -1,5 +1,16 @@
 # Classic HUD, automatic reload, furniture navigation, death audio
 
+## Work-Death Balance damage tuning
+
+- Player rifle: **17.5 damage** per body hit (previously 35), using the float
+  `Player.BULLET_DAMAGE` constant. Head multipliers remain zombie ×2.5 / boss ×1.5.
+- Grenade explosion: **320 maximum damage** (previously 160), same 5 m linear
+  falloff, wall occlusion, self-damage and 15 s cooldown. At 1 m it deals 256;
+  at 2.5 m it deals 160; outside 5 m it deals none.
+- Alien Grunt hornet damage is **unchanged**, including its progression by rank.
+- `tools/test_rebalance_branding.gd`: 14 checks, including real rifle body/head
+  hits and exact explosion/self-damage values. All previous gameplay suites pass.
+
 ## HUD
 
 `scripts/game_hud.gd` replaces the debug-style text block with translucent black