fix(character): always write the GM, activity and social blocks on construction

Live wrote all three optional blocks of the character component in every
player construction (9,726 LOT 1 constructions: gm_pvp_info with is_gm
false and gm_level 0 for civilians, current_activity Some(None) on 9,620,
social_info always Some with guild 0 and an empty name). DLU wrote each one
only after something set its dirty flag, so civilians got none of them.
Serializations are unchanged (still only when dirty).

Writing the social block every time exposed two bugs in it: the guild ID
was never initialized (now 0), and the guild name was written with
sizeof(wchar_t) (4 on Linux) bits per character, reading past the end of
the UTF-16 string; it is now written as 16-bit characters.

Test: ReplicaConstructionTest.CharacterConstructionAlwaysWritesGmActivityAndSocialBlocks.

Check in game: log in as a civilian and as a GM, with a second player
watching; both see each other normally (name tags, GM tag/level for the
GM, no PvP flag), and starting a quickbuild or pet taming still shows the
activity to the other player.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

dGame/dComponents/CharacterComponent.h

@@ -452,7 +452,7 @@ private:
 	/**
 	 * The guild this character is in
 	 */
-	LWOOBJID m_GuildID;
+	LWOOBJID m_GuildID = LWOOBJID_EMPTY;
 
 	/**
 	 * The name of the guild this character is in