fix: R key resets camera angles only; consume all SpellCastTargets bytes

- CameraController::resetAngles(): new method that only resets yaw/pitch
  without teleporting the player. R key now calls resetAngles() instead
  of reset() so pressing R no longer moves the character to spawn.
  The full reset() (position + angles) is still used on world-entry and
  respawn via application.cpp.

- packet_parsers_classic: parseSpellStart now calls
  skipClassicSpellCastTargets() to consume all target payload bytes
  (UNIT, ITEM, SOURCE_LOCATION, DEST_LOCATION, etc.) instead of only
  handling UNIT/OBJECT. Prevents packet-read corruption for ground-
  targeted AoE spells.

- packet_parsers_tbc: added skipTbcSpellCastTargets() static helper
  (uint32 targetFlags, full payload coverage including TRADE_ITEM and
  STRING targets). parseSpellStart now uses it.

include/rendering/camera_controller.hpp

@@ -44,6 +44,7 @@ public:
     }
 
     void reset();
+    void resetAngles();
     void teleportTo(const glm::vec3& pos);
     void setOnlineMode(bool online) { onlineMode = online; }