feat: Add Gradio UI apps for AI services

- embeddings.py: BGE embeddings demo with similarity
- stt.py: Whisper speech-to-text demo
- tts.py: XTTS text-to-speech demo
- theme.py: Shared DaviesTechLabs Gradio theme
- K8s deployments for each app

requirements.txt

@@ -0,0 +1,12 @@
+# Gradio Demo Services - Common Requirements
+gradio>=4.44.0
+httpx>=0.27.0
+numpy>=1.26.0
+mlflow>=2.10.0
+psycopg2-binary>=2.9.0
+
+# Audio processing
+soundfile>=0.12.0
+
+# Async support
+anyio>=4.0.0