refactor(async): migrate from blocking HTTP to async/await with tokio

Replace reqwest::blocking with async reqwest across the entire codebase.
All command execute functions, registry API calls (packagist, downloader,
resolver, lockfile), and the main entry point now use async/await with
the tokio runtime. The pubgrub resolver runs on spawn_blocking since its
DependencyProvider trait is synchronous, using Handle::block_on for
async I/O within that context.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/crates/mozart/src/main.rs b/crates/mozart/src/main.rs
index ebe84e5..04dd6d1 100644
--- a/crates/mozart/src/main.rs
+++ b/crates/mozart/src/main.rs
@@ -1,7 +1,7 @@
 use clap::Parser;
 use mozart::commands;
 use mozart_core::exit_code;
-use tracing_subscriber::{fmt, prelude::*, EnvFilter};
+use tracing_subscriber::{EnvFilter, fmt, prelude::*};
 
 fn init_tracing(profile: bool, verbose: u8, quiet: bool) {
     // MOZART_LOG environment variable takes highest priority.
@@ -37,10 +37,11 @@ fn init_tracing(profile: bool, verbose: u8, quiet: bool) {
     // Otherwise: no subscriber installed → tracing macros are effectively zero-cost no-ops.
 }
 
-fn main() {
+#[tokio::main]
+async fn main() {
     let cli = commands::Cli::parse();
     init_tracing(cli.profile, cli.verbose, cli.quiet);
-    match commands::execute(&cli) {
+    match commands::execute(&cli).await {
         Ok(()) => {}
         Err(e) => {
             // Check if this is a structured MozartError with a specific exit code.