Add contributor and docs for force_viewport_screenshot feature

- Add TheRedRad to CONTRIBUTORS.md for PR #1694
- Document force_viewport_screenshot in API parameters reference
- Add viewport screenshot note in browser-crawler-config guide
- Add viewport-only screenshot example in screenshot docs

docs/md_v2/api/parameters.md

@@ -174,6 +174,7 @@ If your page is a single-page app with repeated JS updates, set `js_only=True` i
 | **`screenshot`**                           | `bool` (False)      | Capture a screenshot (base64) in `result.screenshot`.                                                     |
 | **`screenshot_wait_for`**                  | `float or None`     | Extra wait time before the screenshot.                                                                    |
 | **`screenshot_height_threshold`**          | `int` (~20000)      | If the page is taller than this, alternate screenshot strategies are used.                                |
+| **`force_viewport_screenshot`**            | `bool` (False)      | If `True`, always captures a viewport-only screenshot regardless of page height. Faster and smaller than full-page screenshots. |
 | **`pdf`**                                  | `bool` (False)      | If `True`, returns a PDF in `result.pdf`.                                                                 |
 | **`capture_mhtml`**                        | `bool` (False)      | If `True`, captures an MHTML snapshot of the page in `result.mhtml`. MHTML includes all page resources (CSS, images, etc.) in a single file. |
 | **`image_description_min_word_threshold`** | `int` (~50)         | Minimum words for an image's alt text or description to be considered valid.                              |

docs/md_v2/core/browser-crawler-config.md

@@ -259,9 +259,10 @@ class CrawlerRunConfig:
    - A CSS or JS expression to wait for before extracting content.  
    - Common usage: `wait_for="css:.main-loaded"` or `wait_for="js:() => window.loaded === true"`.
 
-8.⠀**`screenshot`**, **`pdf`**, & **`capture_mhtml`**:  
-   - If `True`, captures a screenshot, PDF, or MHTML snapshot after the page is fully loaded.  
+8.⠀**`screenshot`**, **`pdf`**, & **`capture_mhtml`**:
+   - If `True`, captures a screenshot, PDF, or MHTML snapshot after the page is fully loaded.
    - The results go to `result.screenshot` (base64), `result.pdf` (bytes), or `result.mhtml` (string).
+   - Use `force_viewport_screenshot=True` to capture only the visible viewport instead of the full page. This is faster and produces smaller images when you don't need a full-page screenshot.
 
 9.⠀**Location Parameters**:  
    - **`locale`**: Browser's locale (e.g., `"en-US"`, `"fr-FR"`) for language preferences