refactor(platform): move platform.rs to platform/mod.rs

Restructure the platform module into a directory to allow for future sub-module expansion.

src/platform/mod.rs

@@ -0,0 +1,66 @@
+// SPDX-FileCopyrightText: 2026-Present Nils Andreas Svee mailto:contact@lochnair.net (github @Lochnair)
+//
+// SPDX-License-Identifier: MPL-2.0
+
+use std::error::Error;
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub(crate) struct InterfaceStats {
+    pub(crate) rx_bytes: u64,
+    pub(crate) tx_bytes: u64,
+}
+
+pub(crate) trait InterfaceStatsProvider: Send {
+    type Error: Error + Send + Sync + 'static;
+
+    fn read_stats(&mut self, interface: &str) -> Result<InterfaceStats, Self::Error>;
+}
+
+pub(crate) trait TrafficControlBackend: Send {
+    type Error: Error + Send + Sync + 'static;
+    type Handle: Send + 'static;
+
+    fn find_shaper(&mut self, interface: &str) -> Result<Self::Handle, Self::Error>;
+
+    fn set_rate(
+        &mut self,
+        shaper: &Self::Handle,
+        bandwidth_kbit: u64,
+        dry_run: bool,
+    ) -> Result<(), Self::Error>;
+}
+
+#[cfg(not(target_os = "linux"))]
+mod noop;
+
+#[cfg(target_os = "freebsd")]
+mod freebsd;
+
+#[cfg(target_os = "linux")]
+mod linux;
+
+#[cfg(target_os = "macos")]
+mod macos;
+
+#[cfg(unix)]
+pub mod unix;
+
+#[cfg(not(any(target_os = "freebsd", target_os = "linux", target_os = "macos")))]
+mod unsupported;
+
+#[cfg(target_os = "freebsd")]
+use freebsd as imp;
+
+#[cfg(target_os = "linux")]
+use linux as imp;
+
+#[cfg(target_os = "macos")]
+use macos as imp;
+
+#[cfg(not(any(target_os = "freebsd", target_os = "linux", target_os = "macos")))]
+use unsupported as imp;
+
+pub(crate) use imp::{
+    PlatformInterfaceStats, PlatformTrafficControl, interface_stats_provider,
+    traffic_control_backend, warn_platform_limitations,
+};