Adds:
- bomb_objective.gd: server-authoritative bomb state machine (IDLE→PLANTED→EXPLODED/DEFUSED)
- plant_bomb(player_id, pos) - T-side only, LIVE phase, inside bombsite
- defuse_bomb(player_id) - CT-side only, near bomb, 5s timer
- cancel_defuse(player_id) - if defuser moves or is killed
- bomb_explode() - configurable radius damage (10m lethal, 15m half)
- 40s bomb timer (configurable)
- Full query API: is_bomb_planted(), get_bomb_position(), get_bomb_timer()
- Signals: bomb_planted, bomb_defused, bomb_exploded, defuse_started, defuse_cancelled
- Connected to RoundManager via GameServer for round-end outcomes
- bomb_carrier.gd: client-side bomb carrier UI
- Bomb status/defuse progress UI updates
- Direction indicator to planted bomb
- "Hold E to defuse" prompt for CT near bomb
- "Hold E to plant" prompt for T with bomb in bombsite
- test_range.tscn: BombsiteA (south-west, -20,0,-5) and BombsiteB (north-east, 15,0,20)
- 8x4m Area3D zones with BoxShape3D collision
- PlantPosition Marker3D children
- Group 'bomb_sites' for server discovery
- game_server.gd: BombObjective integration in _ready()
- Creates and wires BombObjective to RoundManager, TeamManager, DamageProcessor
- Registers bomb sites from scene tree
- Connects bomb_exploded/bomb_defused → RoundManager.end_round()
- Connects round_ended → bomb.reset()
