docs(web): add troubleshooting guide and improve navigation

- Create troubleshooting page with debugging steps and known issues
- Add hero subtitle and quick links to landing page
- Document kubectl-cnpg backup command syntax changes
- Include migration notes for users switching from in-tree backup

Signed-off-by: Jeff Mealo <[email protected]>

Author: jmealo

web/docs/intro.md

@@ -23,9 +23,14 @@ for detailed instructions.
 
 To use the Barman Cloud Plugin, you need:
 
-- [CloudNativePG](https://cloudnative-pg.io) version **1.26** <!-- ADD WHEN 1.27 IS OUT "or later" -->
+- [CloudNativePG](https://cloudnative-pg.io) version **1.26** or later
+  - **Version 1.27.0 or later is strongly recommended** for enhanced plugin error and status reporting
+  - See the [upgrade guide](https://cloudnative-pg.io/documentation/current/installation_upgrade) if you need to upgrade
 - [cert-manager](https://cert-manager.io/) to enable TLS communication between
   the plugin and the operator
+- [kubectl-cnpg plugin](https://cloudnative-pg.io/documentation/current/kubectl-plugin/) (recommended)
+  - Provides enhanced debugging and status checking capabilities
+  - Install via `kubectl krew install cnpg` or download from [releases](https://github.com/cloudnative-pg/cloudnative-pg/releases)
 
 ## Key Features