insight-chat: code-review polish on get_faces_in_photo

- Drop redundant `use anyhow::Context` inside has_any_faces (already
  imported at the module level).
- Drop dead `.unwrap_or("?")` on bound faces — the vec is filtered to
  is_some() so the fallback can never fire.
- Reorder the face_dao constructor param + initializer to match the
  struct declaration (between tag_dao and knowledge_dao). Update both
  state.rs call sites and populate_knowledge.rs to match.
- Hold face_dao lock once across the library-resolver loop instead of
  reacquiring per iteration.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/state.rs

@@ -234,8 +234,8 @@ impl Default for AppState {
             location_dao.clone(),
             search_dao.clone(),
             tag_dao.clone(),
-            knowledge_dao,
             face_dao.clone(),
+            knowledge_dao,
             libraries_vec.clone(),
         );
 
@@ -376,8 +376,8 @@ impl AppState {
             location_dao.clone(),
             search_dao.clone(),
             tag_dao.clone(),
-            knowledge_dao,
             face_dao.clone(),
+            knowledge_dao,
             vec![test_lib],
         );