docs: add NEW tags for pages about new features

docs/voice-agent/pre-call-data-fetch.mdx

@@ -1,6 +1,7 @@
 ---
 title: "Pre-Call Data Fetch"
 description: "Fetch customer data from your CRM or ERP before the call starts, so your voice agent can greet callers by name and reference their account details."
+tag: "NEW"
 ---
 
 Pre-Call Data Fetch allows you to enrich the call context with external data before the voice agent starts speaking. When enabled on the **Start Call** node, Dograh sends an HTTP request to your API as soon as a call is initiated. While the response is loading, the caller hears a ring-back tone. Once the data arrives, it is merged into the call's [initial context](/core-concepts/context-and-variables#initial_context) and becomes available as template variables in your prompts and greetings.

docs/voice-agent/pre-recorded-audio.mdx

@@ -1,6 +1,7 @@
 ---
 title: "Pre-recorded Audio"
 description: "Build hybrid voice agents that combine pre-recorded audio with dynamic text generation for lower latency, reduced TTS costs, and natural-sounding conversations."
+tag: "NEW"
 ---
 
 Custom recordings allow you to build **hybrid voice agents** that use your own pre-recorded audio for key parts of the conversation, while falling back to LLM-generated speech (via a cloned voice) for dynamic responses. This gives you the best of both worlds — the emotional depth of real human speech and the flexibility of AI-generated dialogue.