feat: add changelogs for aig + add missing redirects (#24727)

Co-authored-by: Tarush <[email protected]>

Author: tarushnagpal

public/__redirects

@@ -171,6 +171,8 @@
 /ai-gateway/configuration/caching/ /ai-gateway/features/caching/ 301
 /ai-gateway/configuration/rate-limiting/ /ai-gateway/features/rate-limiting/ 301
 /ai-gateway/configuration/custom-metadata/ /ai-gateway/observability/custom-metadata/ 301
+/ai-gateway/universal/ /ai-gateway/usage/universal/ 301
+/ai-gateway/chat-completion/ /ai-gateway/usage/chat-completion/ 301
 
 # agents
 /agents/capabilities/mcp-server/ /agents/model-context-protocol/ 301

src/content/release-notes/ai-gateway.yaml

@@ -3,6 +3,14 @@ link: "/ai-gateway/changelog/"
 productName: AI Gateway
 productLink: "/ai-gateway/"
 entries:
+  - publish_date: "2025-08-25"
+    title: Dynamic routing
+    description: |-
+      Introduced [Dynamic routing](/ai-gateway/routing/dynamic-routing/) to help manage AI provider interactions effectively, ensuring your applications remain responsive and reliable.
+  - publish_date: "2025-08-21"
+    title: Bring your own keys (BYOK)
+    description: |-
+      Introduced [Bring your own keys (BYOK)](/ai-gateway/configuration/byok/) allowing you to save your ai provider keys directly in the AI Gateway dashboard.
   - publish_date: "2025-06-18"
     title: New GA providers
     description: |-