refactor(promise): rewrite promise bodies to async/await

Mechanically convert promise-returning function bodies to async/await:
resolve() returns the value directly, forwarding calls get .await, and
simple .then chains become await sequences. Also collapse the installer
double-Option (Result<Option<Option<PhpMixed>>> -> Result<Option<PhpMixed>>).

Hard spots that depend on the Loop::wait / job-machine boundary
(accept/reject orchestration, closures capturing &mut self, batch waits)
are left intact and marked with TODO(phase-c-promise) for manual porting.
The crate does not compile yet; traits still need #[async_trait].

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/crates/shirabe/src/util/filesystem.rs b/crates/shirabe/src/util/filesystem.rs
index 39b5e6b..1bf4673 100644
--- a/crates/shirabe/src/util/filesystem.rs
+++ b/crates/shirabe/src/util/filesystem.rs
@@ -135,9 +135,7 @@ impl Filesystem {
     pub async fn remove_directory_async(&mut self, directory: &str) -> anyhow::Result<bool> {
         let edge_case_result = self.remove_edge_cases(directory, true)?;
         if let Some(r) = edge_case_result {
-            return Ok(shirabe_external_packages::react::promise::resolve(Some(
-                PhpMixed::Bool(r),
-            )));
+            return Ok(r);
         }
 
         let cmd: Vec<String> = if Platform::is_windows() {
@@ -151,6 +149,9 @@ impl Filesystem {
             vec!["rm".to_string(), "-rf".to_string(), directory.to_string()]
         };
 
+        // TODO(phase-c-promise): execute_async is now async fn -> Result<Process>; the .then_boxed continuation that
+        // inspects the process result and flattens into a recursive removeDirectoryPhp fallback needs job-machine
+        // boundary design before it can become a flat await chain.
         let promise = self.get_process().execute_async(
             PhpMixed::List(
                 cmd.iter()