README: what works, what is partial, and what is not built yet

- the "Not built yet" paragraph catches up with the last two weeks: guilds, the pet bar, fishing, the dressing room, macros and key bindings are in, and the list is now battlegrounds and honor, the auction house, and the unfinished half of addon support
- third-party addons are stated as partial: AtlasLoot and Bagnon run, and the addon API fills in as more addons are tried
- the UI line names the guild, macro and key-binding windows among the classic windows it drives

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

README.md

@@ -38,7 +38,7 @@ and no bundled game assets.
 - **UI:** a from-scratch FrameXML + Lua engine driving the built-in interface, from the login and
   character screens through the full HUD, the classic windows (guild, macros and key bindings
   included), chat, nameplates, floating combat text and tooltips; third-party addons load from
-  your own `Interface/AddOns`.
+  your own `Interface/AddOns` (partial — see below).
 - **Combat:** melee on the faithful swing law, ranged and Auto Shot, casting with GCD and
   cooldowns, combo points, crowd control that really holds you, and the spell visual pipeline.
 - **Audio:** music, ambience and SFX under the client's own selection and crossfade rules, with
@@ -46,7 +46,8 @@ and no bundled game assets.
 
 ## Not built yet
 
-The auction house, and battlegrounds and honor.
+Battlegrounds and honor, and the auction house. Third-party addons are partial: AtlasLoot and
+Bagnon run, and the addon API fills in as other addons are tried.
 
 ## Running it