Add search/metadata API endpoint

- Add MetadataSearchRequest, SearchResponse, SearchAssetResult,
  SearchAlbumResult, SearchFacet, SearchFacetCount models
- Create SearchApi with SearchMetadataBuilder supporting 35+ filters
- Support filtering by location, dates, camera info, favorites,
  tags, people, albums, text search, and more
- Integrate into Client with client.search().metadata() API

src/client.rs

@@ -1,6 +1,6 @@
 //! Client for interacting with the Immich API
 
-use crate::apis::{AlbumsApi, AssetsApi, ServerApi, TimelineApi};
+use crate::apis::{AlbumsApi, AssetsApi, SearchApi, ServerApi, TimelineApi};
 use crate::error::{ImmichError, Result};
 use std::sync::Arc;
 use std::time::Duration;
@@ -201,6 +201,11 @@ impl Client {
         AssetsApi::new(self.clone())
     }
 
+    /// Access the search API
+    pub fn search(&self) -> SearchApi {
+        SearchApi::new(self.clone())
+    }
+
     /// Access the server API
     pub fn server(&self) -> ServerApi {
         ServerApi::new(self.clone())