refactor(core): remove hotpath profiling (#2394)

hotpath adds noticeable overhead on hot paths, so remove the optional
profiling integration while keeping direct quanta::Instant timing.

easytier/src/easytier-core.rs

@@ -1,11 +1,5 @@
 use easytier::core;
 
-#[cfg(all(
-    feature = "hotpath-alloc",
-    any(feature = "jemalloc", feature = "mimalloc")
-))]
-compile_error!("feature `hotpath-alloc` cannot be enabled together with `jemalloc` or `mimalloc`");
-
 #[cfg(all(feature = "mimalloc", not(feature = "jemalloc")))]
 use mimalloc::MiMalloc;
 
@@ -30,16 +24,6 @@ pub static malloc_conf: &[u8] = b"retain:false\0";
 rust_i18n::i18n!("locales", fallback = "en");
 
 #[tokio::main(flavor = "current_thread")]
-#[cfg_attr(
-    all(
-        feature = "hotpath",
-        not(all(
-            feature = "hotpath-alloc",
-            any(feature = "jemalloc", feature = "mimalloc")
-        ))
-    ),
-    hotpath::main
-)]
 async fn main() -> std::process::ExitCode {
     core::main().await
 }