Fix accessibility command for Playwright 1.57+

Playwright 1.57.0 removed `page.accessibility.snapshot()` after 3 years
of deprecation. This updates the accessibility command to use the new
`locator.aria_snapshot()` API instead.

Note: The output format has changed due to the new API returning a
different accessibility tree structure (using semantic landmark roles
like banner, main, contentinfo, navigation).

Author: claude

shot_scraper/cli.py

@@ -702,9 +702,10 @@ def accessibility(
         skip_or_fail(response, skip, fail)
         if javascript:
             _evaluate_js(page, javascript)
-        snapshot = page.accessibility.snapshot()
+        snapshot = page.locator("body").aria_snapshot()
         browser_obj.close()
-    output.write(json.dumps(snapshot, indent=4))
+    # aria_snapshot() returns YAML, parse it for JSON output
+    output.write(json.dumps(yaml.safe_load(snapshot), indent=4))
     output.write("\n")