feat: increase turn timeout to 10s and expand help screen

- Turn timeout 5s → 10s for more comfortable gameplay
- Help screen now covers: lobby, exploration, combat, shop, classes,
  multiplayer tips, and general tips including skill tree controls

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

config/config.go

@@ -63,7 +63,7 @@ func defaults() Config {
 	return Config{
 		Server: ServerConfig{SSHPort: 2222, HTTPPort: 8080},
 		Game: GameConfig{
-			TurnTimeoutSec: 5, MaxPlayers: 4, MaxFloors: 20,
+			TurnTimeoutSec: 10, MaxPlayers: 4, MaxFloors: 20,
 			CoopBonus: 0.10, InventoryLimit: 10, SkillUses: 3,
 		},
 		Combat: CombatConfig{FleeChance: 0.50, MonsterScaling: 1.15, SoloHPReduction: 0.50},

config/config_test.go

@@ -16,8 +16,8 @@ func TestLoadDefaults(t *testing.T) {
 	if cfg.Server.HTTPPort != 8080 {
 		t.Errorf("expected HTTP port 8080, got %d", cfg.Server.HTTPPort)
 	}
-	if cfg.Game.TurnTimeoutSec != 5 {
-		t.Errorf("expected turn timeout 5, got %d", cfg.Game.TurnTimeoutSec)
+	if cfg.Game.TurnTimeoutSec != 10 {
+		t.Errorf("expected turn timeout 10, got %d", cfg.Game.TurnTimeoutSec)
 	}
 	if cfg.Game.MaxPlayers != 4 {
 		t.Errorf("expected max players 4, got %d", cfg.Game.MaxPlayers)