Add screenshots and embed them in documentation pages

Getting-Started.md

@@ -2,6 +2,8 @@
 
 After [[Installation]], launch Roster from the application menu or run `roster` (Flatpak: `flatpak run cz.bugsy.roster`).
 
+![Roster main window](main.png)
+
 ## Sending a Request
 
 1. The app opens with a new request tab

History.md

@@ -6,6 +6,8 @@ Every request you send is automatically saved to history and persists across ses
 
 History appears in the **bottom panel** of the main window. Each entry shows method, URL, status code, timestamp, and response time, sorted newest first.
 
+![History panel](history.png)
+
 Click any entry to open it in a new tab — you can modify and resend it.
 
 ## Storage

Import.md

@@ -29,6 +29,8 @@ Imports all defined operations as SOAP requests, including:
 
 ### OpenAPI / Swagger
 
+![Import from OpenAPI dialog](load_openapi.png)
+
 1. Click the **Import** button (papyrus icon) in the sidebar toolbar
 2. Select **"Import from OpenAPI / Swagger"**
 3. Enter the **Spec URL** of the OpenAPI/Swagger definition (must start with `http://` or `https://`)

Variables.md

@@ -15,6 +15,8 @@ Authorization: Bearer {{api_token}}
 
 Open via **⋯ → Manage Environments** next to the project name in the sidebar.
 
+![Manage Environments dialog](variables.png)
+
 - **Add environment:** click **+** next to the environment list
 - **Add variable:** click **+** at the bottom of the variable list
 - **Delete:** click **×** on the variable row or environment header