Docs: Document missing CLI flags and integrations (#3182)

* docs: document missing flags and integrations

* docs: remove invalid --refresh-shared-infra from upgrade command

* docs: address PR feedback for extension and integration flags

* docs: reorder extension add options to match CLI help

Author: DyanGalih

docs/reference/extensions.md

@@ -26,7 +26,7 @@ specify extension add <name>
 | --------------- | -------------------------------------------------------- |
 | `--dev`         | Install from a local directory (for development)         |
 | `--from <url>`  | Install from a custom URL instead of the catalog         |
-| `--force`       | Overwrite if already installed                           |
+| `--force`       | Overwrite if the extension is already installed          |
 | `--priority <N>`| Resolution priority (default: 10; lower = higher precedence) |
 
 Installs an extension from the catalog, a URL, or a local directory. Extension commands are automatically registered with the currently installed AI coding agent integration.