refactor: enable clippy::arithmetic_side_effects lint

src/net/http.rs

@@ -115,6 +115,7 @@ where
 }
 
 /// Converts the URL to expiration and stale timestamps.
+#[expect(clippy::arithmetic_side_effects)]
 fn http_url_cache_timestamps(url: &str, mimetype: Option<&str>) -> (i64, i64) {
     let now = time();
 
@@ -173,6 +174,7 @@ async fn http_cache_put(context: &Context, url: &str, response: &Response) -> Re
 /// Retrieves the binary from HTTP cache.
 ///
 /// Also returns if the response is stale and should be revalidated in the background.
+#[expect(clippy::arithmetic_side_effects)]
 async fn http_cache_get(context: &Context, url: &str) -> Result<Option<(Response, bool)>> {
     let now = time();
     let Some((blob_name, mimetype, encoding, stale_timestamp)) = context

src/net/proxy.rs

@@ -174,6 +174,7 @@ pub enum ProxyConfig {
 }
 
 /// Constructs HTTP/1.1 `CONNECT` request for HTTP(S) proxy.
+#[expect(clippy::arithmetic_side_effects)]
 fn http_connect_request(host: &str, port: u16, auth: Option<(&str, &str)>) -> String {
     // According to <https://datatracker.ietf.org/doc/html/rfc7230#section-5.4>
     // clients MUST send `Host:` header in HTTP/1.1 requests,
@@ -322,6 +323,7 @@ impl ProxyConfig {
     /// config into `proxy_url` if `proxy_url` is unset or empty.
     ///
     /// Unsets `socks5_host`, `socks5_port`, `socks5_user` and `socks5_password` in any case.
+    #[expect(clippy::arithmetic_side_effects)]
     async fn migrate_socks_config(sql: &Sql) -> Result<()> {
         if sql.get_raw_config("proxy_url").await?.is_none() {
             // Load legacy SOCKS5 settings.