fix(http): avoid nested tokio runtime panic in download path

The CurlDownloader owned a tokio runtime and block_on'd reqwest from its
sync tick(), while the repository/installer/downloader sync bridges each
created another Runtime and block_on'd async fns that reach that leaf.
Driving one Runtime::block_on from within another panics with "Cannot
start a runtime from within a runtime", hit by `require` when fetching
p2 metadata.

Switch CurlDownloader to a blocking reqwest client (its own internal
thread, never nested) and replace the per-call Runtime::new().block_on
bridges with a no-reactor sync_executor::block_on helper. No awaited
future parks on a reactor once the only async I/O is blocking, so the
helper can be nested freely.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/crates/shirabe/src/package/version/version_guesser.rs b/crates/shirabe/src/package/version/version_guesser.rs
index f18f363..8e8cc32 100644
--- a/crates/shirabe/src/package/version/version_guesser.rs
+++ b/crates/shirabe/src/package/version/version_guesser.rs
@@ -10,6 +10,7 @@ use crate::util::HttpDownloader;
 use crate::util::Platform;
 use crate::util::ProcessExecutor;
 use crate::util::Svn as SvnUtil;
+use crate::util::sync_executor;
 use anyhow::Result;
 use indexmap::IndexMap;
 use shirabe_external_packages::composer::pcre::{CaptureKey, Preg};
@@ -543,7 +544,7 @@ impl VersionGuesser {
                         },
                         &scm_cmdline,
                     );
-                    let mut process = tokio::runtime::Runtime::new().unwrap().block_on(
+                    let mut process = sync_executor::block_on(
                         self.process
                             .borrow_mut()
                             .execute_async(&cmd_line, Some(path)),