docs: mark legacy Vapi Voices and reorganize documentation

- Add Legacy Voices section with deprecation notice
- Move Paige, Spencer, Neha, Harry, Cole, Hana, and Lily to Legacy
- Keep Rohan, Elliot, and Savannah as Active Voices
- Add callout explaining legacy voice transition

Closes VAP-11231

Author: vapi-tasker[bot]

fern/providers/voice/vapi-voices.mdx

@@ -15,7 +15,9 @@ Vapi Voices is our carefully curated selection of high-quality voices designed t
 - **Ready to Use**: Pre-optimized for your applications
 - **Consistent**: Reliable quality in all interactions
 
-## Available Voices
+## Active Voices
+
+These voices are fully supported and recommended for new assistants.
 
 ### Rohan
 - **Gender**: Male
@@ -24,72 +26,83 @@ Vapi Voices is our carefully curated selection of high-quality voices designed t
 - **Characteristics**: Bright, optimistic, cheerful, energetic
 - **Sample Audio**: <audio controls src="/static/audio/rohan-sample.wav">Your browser does not support the audio element.</audio>
 
-### Neha
-- **Gender**: Female
-- **Accent**: Indian American
-- **Age**: 30 years old
-- **Characteristics**: Professional, charming
-- **Sample Audio**: <audio controls src="/static/audio/neha-sample.wav">Your browser does not support the audio element.</audio>
-
-### Hana
-- **Gender**: Female
-- **Accent**: American
-- **Age**: 22 years old
-- **Characteristics**: Soft, soothing, gentle
-- **Sample Audio**: <audio controls src="/static/audio/hana-sample.wav">Your browser does not support the audio element.</audio>
-
-### Harry
-- **Gender**: Male
-- **Accent**: American
-- **Age**: 24 years old
-- **Characteristics**: Clear, energetic, professional
-- **Sample Audio**: <audio controls src="/static/audio/harry-sample.wav">Your browser does not support the audio element.</audio>
-
 ### Elliot
 - **Gender**: Male
 - **Accent**: Canadian
 - **Age**: 25 years old
 - **Characteristics**: Soothing, friendly, professional
 - **Sample Audio**: <audio controls src="/static/audio/elliot-sample.wav">Your browser does not support the audio element.</audio>
 
-### Lily
+### Savannah
 - **Gender**: Female
-- **Accent**: Asian American
+- **Accent**: American (Southern)
 - **Age**: 25 years old
-- **Characteristics**: Bright personality, bubbly, cheerful
-- **Sample Audio**: <audio controls src="/static/audio/lily-sample.wav">Your browser does not support the audio element.</audio>
+- **Characteristics**: Southern American accent
+- **Sample Audio**: <audio controls src="/static/audio/savannah-sample.wav">Your browser does not support the audio element.</audio>
+
+## Legacy Voices
+
+<Warning>
+The following voices are classified as **Legacy** and are being phased out:
+- **Existing assistants** using these voices may continue to use them during the transition period
+- **New assistants cannot be created** using legacy voices
+- Legacy voices will be fully retired in a future update
 
-### Paige
+We recommend migrating to one of the Active Voices listed above.
+</Warning>
+
+### Paige (Legacy)
 - **Gender**: Female
 - **Accent**: American
 - **Age**: 26 years old
 - **Characteristics**: Deeper tone, calming, professional
 - **Sample Audio**: <audio controls src="/static/audio/paige-sample.wav">Your browser does not support the audio element.</audio>
 
-### Cole
+### Spencer (Legacy)
+- **Gender**: Female
+- **Accent**: American
+- **Age**: 26 years old
+- **Characteristics**: Energetic, quippy, lighthearted, cheeky, amused
+- **Sample Audio**: <audio controls src="/static/audio/spencer-sample.wav">Your browser does not support the audio element.</audio>
+
+### Neha (Legacy)
+- **Gender**: Female
+- **Accent**: Indian American
+- **Age**: 30 years old
+- **Characteristics**: Professional, charming
+- **Sample Audio**: <audio controls src="/static/audio/neha-sample.wav">Your browser does not support the audio element.</audio>
+
+### Harry (Legacy)
+- **Gender**: Male
+- **Accent**: American
+- **Age**: 24 years old
+- **Characteristics**: Clear, energetic, professional
+- **Sample Audio**: <audio controls src="/static/audio/harry-sample.wav">Your browser does not support the audio element.</audio>
+
+### Cole (Legacy)
 - **Gender**: Male
 - **Accent**: American
 - **Age**: 22 years old
 - **Characteristics**: Deeper tone, calming, professional
 - **Sample Audio**: <audio controls src="/static/audio/cole-sample.wav">Your browser does not support the audio element.</audio>
 
-### Savannah
+### Hana (Legacy)
 - **Gender**: Female
-- **Accent**: American (Southern)
-- **Age**: 25 years old
-- **Characteristics**: Southern American accent
-- **Sample Audio**: <audio controls src="/static/audio/savannah-sample.wav">Your browser does not support the audio element.</audio>
+- **Accent**: American
+- **Age**: 22 years old
+- **Characteristics**: Soft, soothing, gentle
+- **Sample Audio**: <audio controls src="/static/audio/hana-sample.wav">Your browser does not support the audio element.</audio>
 
-### Spencer
+### Lily (Legacy)
 - **Gender**: Female
-- **Accent**: American
-- **Age**: 26 years old
-- **Characteristics**: Energetic, quippy, lighthearted, cheeky, amused
-- **Sample Audio**: <audio controls src="/static/audio/spencer-sample.wav">Your browser does not support the audio element.</audio>
+- **Accent**: Asian American
+- **Age**: 25 years old
+- **Characteristics**: Bright personality, bubbly, cheerful
+- **Sample Audio**: <audio controls src="/static/audio/lily-sample.wav">Your browser does not support the audio element.</audio>
 
 ## How to Use
 
-1. Select a voice from our collection
+1. Select a voice from our Active Voices collection
 2. Integrate it into your assistant or squad
 3. Start creating voice interactions immediately