feat(ui): entity-anchored dialogue log with keyboard selection

Log entries store entity IDs and resolve display names at render
time from _entity_display lookup — enables retroactive name update
when player learns an NPC's real name. Color index from server
replaces name-hash coloring for stable NPC colors.

Dialogue options: switched RichTextLabel to Label (fixes stacking
bug), added 1/2/3 number key selection, numbered option labels.

Interaction list: added background panel, mouse hover highlighting,
click-to-interact, pointing hand cursor.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

client/scripts/protocol/protocol.gd

@@ -11,7 +11,7 @@ class_name Protocol
 
 ## Protocol version — must match server PROTOCOL_VERSION in bridge/types.rs.
 ## Reject snapshots where version != this value.
-const PROTOCOL_VERSION: int = 9
+const PROTOCOL_VERSION: int = 12
 
 
 # -- Decode: bytes from server → GDScript types --------------------------------