perf: make StoragePath::join and File builders consume self to avoid clones

StoragePath::join deep-cloned the whole Vec<String> (every segment String)
just to append one element. Take self by value and push in place. All callers
pass owned values except PathService::create_file_path, which holds a borrow
and now clones explicitly — the same copy the old &self join already made.

File::with_name / with_folder / with_size took &self and rebuilt the struct,
cloning every carried-over field (id, mime_type, folder_id, blob_hash, ...).
Consume self and mutate only the fields that change. Behaviour is identical;
the fallible builders now drop the input on Err, which is fine for these
rename/move/resize transforms (all current callers replace the file).

Impact is small in practice — with_folder/with_size have no callers and
with_name is test-only, while the one hot join caller (create_file_path)
must copy segments regardless — but the consuming form is the idiomatic one.

Verified: cargo fmt + clippy --all-features --all-targets -D warnings clean;
domain tests (path_service::, entities::file::) pass — 30 + 6.

https://claude.ai/code/session_01UtfkS3nZF1vrF5jNAps6wV

src/infrastructure/services/path_service.rs

@@ -64,7 +64,9 @@ impl PathService {
 
     /// Creates a file path within a folder
     pub fn create_file_path(&self, folder_path: &StoragePath, file_name: &str) -> StoragePath {
-        folder_path.join(file_name)
+        // `join` consumes its receiver to reuse the buffer; we only hold a
+        // borrow here, so clone first — the same copy the old `&self` join did.
+        folder_path.clone().join(file_name)
     }
 
     /// Checks if a path is a direct child of another