clickthrough: block unusable player-summoned portals and rituals

Filter ritual (type 18) and mage portal (type 22) GOs whose creator
is a player not in the local player's party or raid. Completely
unclickable, not just deprioritized.

Also:
- Add wow.isInGroup() shared group membership check (party + raid)
- Add party/raid addresses to shared offsets.zig
- Fix dpslog party member GUID address (was 0xBC7600, correct: 0xBC6F48)
  Verified from client's is_player_in_allowed_list @ 0x4e7f70

IDEAS.md

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+# Ideas
+
+## Transmog Toggle
+Add an option to the TW Options menu to disable all transmogs. Works for the
+local player (we have the real item objects and can look up base entry IDs from
+descriptors). Does NOT work for other players -- the server only sends the
+transmogged item entry in VISIBLE_ITEM fields, and the real entry is never
+transmitted to other clients. Would need server-side support (e.g. a packet
+flag or CVar the server respects) to strip transmogs on other players.
+
+## Minimap Icon Tooltips
+Mouseover popups on minimap tracking blips showing NPC/object name and type.
+Reference implementation already exists -- check how it's done there.
+
+## Unusable Portal Visual + Click Blocking
+Covers summoned ritual objects (type 18: healthstone, summoning portal, ritual
+of refreshment/doom) and mage portals (type 22: GAMEOBJECT_TYPE_SPELLCASTER).
+
+Three states to distinguish:
+1. **Interactable** -- usable, normal rendering
+2. **Not interactable** -- `CallSpellCastHandler` (0x5f8800) returns 0 (wrong faction, not in group)
+3. **Interactable but locked** -- `CallSpellCastHandler` returns 1, `GAMEOBJECT_FLAGS & 0x02` (GO_FLAG_LOCKED) set
+
+Goals:
+- Prevent clicking GOs in states 2 and 3 (clickthrough module, GO filter pass)
+- Render states 2/3 in greyscale or desaturated to visually distinguish from usable ones
+
+Click blocking fits in clickthrough's existing cascade filter (checkObjTypeDetour).
+Greyscale rendering needs research into the client's GO model draw path -- may need
+to intercept material/texture setup or set a per-object color tint before the draw call.
+
+Module: clickthrough (own file, e.g. portal_filter.zig)