fix(assets): add missing .import file for sfx_npc_murmur.ogg

Godot requires .import files for stable uid:// references across
editor sessions. All other audio assets have one — this was missed
in the audio branch PR.

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

client/assets/audio/sfx_npc_murmur.ogg.import

@@ -0,0 +1,19 @@
+[remap]
+
+importer="oggvorbisstr"
+type="AudioStreamOggVorbis"
+uid="uid://caeuztw9ah5h5l"
+path="res://.godot/imported/sfx_npc_murmur.ogg-bfd7592cfea1b592d89f107b6cd33838.oggvorbisstr"
+
+[deps]
+
+source_file="res://assets/audio/sfx_npc_murmur.ogg"
+dest_files=["res://.godot/imported/sfx_npc_murmur.ogg-bfd7592cfea1b592d89f107b6cd33838.oggvorbisstr"]
+
+[params]
+
+loop=false
+loop_offset=0
+bpm=0
+beat_count=0
+bar_beats=4