feat: add title selection window with CMSG_SET_TITLE support

Track player titles from SMSG_TITLE_EARNED into knownTitleBits_ set,
read active title from PLAYER_CHOSEN_TITLE update field (WotLK index
1349), expose via getFormattedTitle()/sendSetTitle() on GameHandler.

Add SetTitlePacket builder (CMSG_SET_TITLE: int32 titleBit, -1=clear).

Titles window (H key) lists all earned titles from CharTitles.dbc,
highlights the active one in gold, and lets the player click to equip
or unequip a title with a single server round-trip.

include/game/update_field_table.hpp

@@ -56,6 +56,7 @@ enum class UF : uint16_t {
     PLAYER_FIELD_BANKBAG_SLOT_1,
     PLAYER_SKILL_INFO_START,
     PLAYER_EXPLORED_ZONES_START,
+    PLAYER_CHOSEN_TITLE,         // Active title index (-1 = no title)
 
     // GameObject fields
     GAMEOBJECT_DISPLAYID,