docs: Update meta content - Integrations and Develop Boundary (#5283)

* docs: Update meta content - Integrations and Develop Boundary

* Update website/content/docs/developing/index.mdx

Co-authored-by: Robin Beck <stellarsquall@users.noreply.github.com>

---------

Co-authored-by: Robin Beck <stellarsquall@users.noreply.github.com>

website/content/docs/developing/building.mdx

@@ -1,7 +1,8 @@
 ---
 layout: docs
 page_title: Build Boundary
-description: Build Boundary from source
+description: >-
+  Learn how to build Boundary from the source. Discover resources to compile a cross-platform build and troubleshoot UI assets.
 ---
 
 # Build Boundary

website/content/docs/developing/index.mdx

@@ -1,7 +1,8 @@
 ---
 layout: docs
 page_title: Develop Boundary
-description: Develop Boundary
+description: >-
+    Discover resources to help you build and develop Boundary.
 ---
 
 # Develop Boundary

website/content/docs/developing/ui.mdx

@@ -1,7 +1,8 @@
 ---
 layout: docs
 page_title: Develop the UI
-description: Develop the Boundary user interface
+description: >-
+    Learn how to develop the Boundary user interface locally for testing. Use dev mode to run a local fork of the UI without building it into the binary.
 ---
 
 # Develop the Boundary user interface

website/content/docs/integrations/index.mdx

@@ -1,8 +1,8 @@
 ---
 layout: docs
 page_title: Integrations
-description: |-
- Integrations that extend Boundary
+description: >-
+    Discover integrations that extend Boundary's features and capabilities.
 ---
 
 # Overview

website/content/docs/integrations/vault/index.mdx

@@ -1,8 +1,8 @@
 ---
 layout: docs
 page_title: Vault integration
-description: |-
- Describes the benefits of integrating HashiCorp Boundary and Vault.
+description: >-
+  Understand the security benefits of integrating Boundary and Vault to manage secrets and broker or inject credentials. Set up Vault as an OIDC bridge provider.
 ---
 
 # Vault integration