Add browser best match option

docs/browser-extension.md

@@ -103,6 +103,8 @@ User story:
   access.
 - Browser matching must treat common KeePass data conventions as real browser
   targets, not just the primary `URL` field.
+- Users who prefer narrow suggestions can ask the extension to show only the
+  strongest match quality returned by KeePassGO.
 
 Expected behavior:
 
@@ -114,6 +116,9 @@ Expected behavior:
   - scheme-less host values such as `gitlab.com`
   - custom URL fields such as `URL1`, `URL2`, and similar KeePass-style URL
     slots
+- The extension settings page exposes `Best match only`.
+- When `Best match only` is enabled, page suggestions and popup search results
+  only show the strongest quality band returned by KeePassGO.
 
 ## Locked Vault Workflow