chore(macos): allow tauri to build on macOS (#9391)

When working on UI stuff for the Tauri clients on macOS it's helpful if
the UI is buildable. This is a first stab at getting a stub client to
launch on macOS with the help of our AI overlords. Feel free to close or
heavily critique if there is a better approach.

rust/bin-shared/src/known_dirs/macos.rs

@@ -1,25 +1,59 @@
+use crate::BUNDLE_ID;
 use std::path::PathBuf;
 
+/// Returns the user's home directory
+fn home_dir() -> Option<PathBuf> {
+    std::env::var_os("HOME").map(PathBuf::from)
+}
+
+/// Path for Tunnel service config that the Tunnel service can write
+#[expect(clippy::unnecessary_wraps)] // Signature must match Windows
 pub fn tunnel_service_config() -> Option<PathBuf> {
-    unimplemented!()
+    Some(
+        PathBuf::from("/Library/Application Support")
+            .join(BUNDLE_ID)
+            .join("config"),
+    )
 }
 
+/// Path for Tunnel service logs
+#[expect(clippy::unnecessary_wraps)] // Signature must match Windows
 pub fn tunnel_service_logs() -> Option<PathBuf> {
-    unimplemented!()
+    Some(PathBuf::from("/Library/Logs").join(BUNDLE_ID))
 }
 
+/// User-specific logs directory
 pub fn logs() -> Option<PathBuf> {
-    unimplemented!()
+    Some(
+        home_dir()?
+            .join("Library/Caches")
+            .join(BUNDLE_ID)
+            .join("logs"),
+    )
 }
 
+/// Runtime directory for temporary files
 pub fn runtime() -> Option<PathBuf> {
-    unimplemented!()
+    let user = std::env::var("USER").ok()?;
+    Some(PathBuf::from("/tmp").join(format!("{}-{}", BUNDLE_ID, user)))
 }
 
+/// User session data directory
 pub fn session() -> Option<PathBuf> {
-    unimplemented!()
+    Some(
+        home_dir()?
+            .join("Library/Application Support")
+            .join(BUNDLE_ID)
+            .join("data"),
+    )
 }
 
+/// User settings/config directory
 pub fn settings() -> Option<PathBuf> {
-    unimplemented!()
+    Some(
+        home_dir()?
+            .join("Library/Preferences")
+            .join(BUNDLE_ID)
+            .join("config"),
+    )
 }

rust/bin-shared/src/uptime/mod.rs

@@ -47,8 +47,7 @@ pub fn get() -> Option<Duration> {
 
 #[cfg(target_os = "macos")]
 pub fn get() -> Option<Duration> {
-    debug_assert!(false, "Not implemented on macOS");
-
+    // TODO: This is stubbed on macOS for now so that mac developers can help out on the Tauri UI.
     None
 }