fix(mop): default Group::SetTargetIcon context arg so 3-arg callers compile

[MadMaxMangos]

Summary

The 5.4.8 raid-markers restore (6b7978ec9) gave Group::SetTargetIcon a new
required fourth parameter — uint8 context — so its signature became
(uint8 id, ObjectGuid whoGuid, ObjectGuid targetGuid, uint8 context). That
broke every existing 3-argument caller, most importantly the shared Eluna
Group:SetTargetIcon binding, which fails to compile against the mangos-four
core with:

error C2660: 'Group::SetTargetIcon': function does not take 3 arguments

Because MangosServer/Eluna is shared across all cores (Classic/TBC/WotLK/Cata/
MoP), it can't call the 4-arg overload unconditionally without breaking the
other cores. The clean fix is core-side: give the new parameter a default.

Change

src/game/WorldHandlers/Group.h — default the new context argument to 0:

-  void SetTargetIcon(uint8 id, ObjectGuid whoGuid, ObjectGuid targetGuid, uint8 context);
+  void SetTargetIcon(uint8 id, ObjectGuid whoGuid, ObjectGuid targetGuid, uint8 context = 0);

context = 0 is a normal target-icon set (matching GroupHandler's default
path). All existing 4-arg callers keep working and the pre-MoP 3-arg call is
source-compatible again — so stock Eluna needs no change.

Testing

• Builds clean against stock Eluna (fd0b208a), no submodule change.
• 253/253 ctest pass.
• Live-verified: server boots and runs; raid markers function.

Supersedes MangosServer/Eluna#8 (close it) — the fix belongs in the core that
changed the signature.

🤖 Generated with Claude Code

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