chore(ui): remove the Streamlit UI (#4097)

Author: ashwinb

docs/docs/building_applications/index.mdx

@@ -35,9 +35,6 @@ Here are the key topics that will help you build effective AI applications:
 - **[Telemetry](./telemetry.mdx)** - Monitor and analyze your agents' performance and behavior
 - **[Safety](./safety.mdx)** - Implement guardrails and safety measures to ensure responsible AI behavior
 
-### 🎮 **Interactive Development**
-- **[Playground](./playground.mdx)** - Interactive environment for testing and developing applications
-
 ## Application Patterns
 
 ### 🤖 **Conversational Agents**

docs/docs/building_applications/playground.mdx

@@ -51,14 +51,6 @@ dependencies = [
     "sqlalchemy[asyncio]>=2.0.41",                    # server - for conversations
 ]
 
-[project.optional-dependencies]
-ui = [
-    "streamlit",
-    "pandas",
-    "llama-stack-client>=0.3.0",
-    "streamlit-option-menu",
-]
-
 [dependency-groups]
 dev = [
     "pytest>=8.4",