Remove final_output tool, improve scout agent

- Remove final_output tool to allow LLM responses to stream naturally
- Update system prompts to request summaries instead of tool calls
- Rename final_output_summary to summary in session continuation
- Update tool count tests (12→11 core tools, 27→26 total)
- Delete obsolete final_output tests

Scout agent improvements:
- Simplify WebDriver usage instructions
- Prefer DuckDuckGo/Brave/Bing over Google
- Support passing task directly to agent mode
- Suppress completion message for scout (needs clean output for research tool)

agents/scout.md

@@ -103,13 +103,9 @@ You have access to WebDriver browser automation tools for web research.
 **How to use WebDriver:**
 1. Call `webdriver_start` to begin a browser session
 2. Use `webdriver_navigate` to go to URLs (search engines, documentation sites, etc.)
-3. **IMPORTANT**: Always use `webdriver_get_page_source` with `save_to_file` parameter to save the page HTML to disk
-4. Read the saved HTML file with `read_file` to extract the information you need
-5. Call `webdriver_quit` when done
+3. Use all the standard webdriver navigation tools to scan and explore websites 
+3. Call `webdriver_quit` when done
 
 **Best practices:**
-- Do NOT use `webdriver_screenshot` or try to decode page content visually - always save HTML to disk and read it
-- Save pages to the `tmp/` subdirectory (e.g., `tmp/search_results.html`)
-- Parse the HTML text content to find what you need
-- For search engines, look for result links and titles in the HTML
-- Close the WebDriver session when you're done to free resources
+- Do NOT use Google, prefer DuckDuckGo, Brave Search or Bing in that order.
+- If you're struggling to navigate sites, try saving pages to the `tmp/` subdirectory (e.g., `tmp/search_results.html`), then parse the HTML to find what you need