Project website + use Apalis crate for task queue (with redis backend)

instead channel and semaphore queue + upgrade to rust 1.99

crates/steep-server/src/env.rs

@@ -11,6 +11,7 @@ pub struct EnvConfig {
     pub gitea_url: String,
     pub gitea_token: String,
     pub gitea_timeout: u64,
+    pub redis_url: String,
     pub metrics_bind_addr: Option<String>,
     pub sandbox_max_iterations: usize,
 }
@@ -25,6 +26,7 @@ pub fn load_config() -> anyhow::Result<EnvConfig> {
     let gitea_url = try_get_env("GITEA_URL")?;
     let gitea_token = try_get_env("GITEA_TOKEN")?;
     let gitea_timeout = try_get_env("GITEA_TIMEOUT")?.parse()?;
+    let redis_url = try_get_env("REDIS_URL")?;
     let metrics_bind_addr = std::env::var("METRICS_BIND_ADDR").ok();
     let sandbox_max_iterations = std::env::var("SANDBOX_MAX_ITERATIONS")
         .ok()
@@ -41,6 +43,7 @@ pub fn load_config() -> anyhow::Result<EnvConfig> {
         gitea_url,
         gitea_token,
         gitea_timeout,
+        redis_url,
         metrics_bind_addr,
         sandbox_max_iterations,
     })