docs: add changelog and readme entries for config upgrade feature

- CHANGELOG: Add notification and upgrade-configs command entries under [1.13.0]
- README: Add Upgrade config files command to Commands table
- README: Add Notifications section with outdated config files description

Co-authored-by: garrytrinder <11563347+garrytrinder@users.noreply.github.com>

Author: Copilot

CHANGELOG.md

@@ -11,6 +11,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added:
 
+- Notification: Detect outdated Dev Proxy config files in workspace and show warning when schema versions don't match installed version
+- Command: `dev-proxy-toolkit.upgrade-configs` - Upgrade config files with Copilot Chat using Dev Proxy MCP tools
 - Quick Fixes: Enable local language model fix now adds or updates `languageModel.enabled: true` for supported plugins only
 
 ### Fixed:

README.md

@@ -34,6 +34,7 @@ Control Dev Proxy directly from VS Code via the Command Palette (`Cmd+Shift+P` /
 | Create configuration file | Dev Proxy installed |
 | Discover URLs to watch | Dev Proxy not running |
 | Generate JWT | Dev Proxy installed |
+| Upgrade config files | Dev Proxy installed |
 
 ### Snippets
 
@@ -201,6 +202,10 @@ Shows Dev Proxy status at a glance:
 - Running state (radio tower icon when active)
 - Error indicator if Dev Proxy is not installed
 
+### Notifications
+
+- **Outdated config files** - On activation, scans workspace for Dev Proxy config files with a schema version that doesn't match the installed Dev Proxy version. Offers a one-click upgrade using Copilot Chat and Dev Proxy MCP tools.
+
 ## Configuration
 
 | Setting | Type | Default | Description |