perf: enable HTTP/2, remove redundant hyper dep, use async RwLock

- Enable HTTP/2 auto-detection in axum (add 'http2' feature)
- Remove direct hyper dependency with 'full' features (already transitive via axum/reqwest)
- Replace std::sync::RwLock with tokio::sync::RwLock in oidc_service.rs and file_system_i18n_service.rs to prevent async deadlocks

Cargo.lock

@@ -723,7 +723,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "39cab71617ae0d63f51a36d69f866391735b51691dbda63cf6f96d042b63efeb"
 dependencies = [
  "libc",
- "windows-sys 0.52.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -1724,7 +1724,7 @@ version = "0.50.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7957b9740744892f114936ab4a57b3f487491bbeafaf8083688b16841a4240e5"
 dependencies = [
- "windows-sys 0.60.2",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -1817,7 +1817,6 @@ dependencies = [
  "http-body",
  "http-body-util",
  "http-range-header",
- "hyper",
  "image",
  "infer",
  "jsonwebtoken",
@@ -2408,7 +2407,7 @@ dependencies = [
  "errno",
  "libc",
  "linux-raw-sys",
- "windows-sys 0.52.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -2927,7 +2926,7 @@ dependencies = [
  "getrandom 0.4.1",
  "once_cell",
  "rustix",
- "windows-sys 0.52.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]