feat(tracing): instrument network requests with tracing spans

Add #[tracing::instrument] and debug logs to all HTTP-calling
functions in mozart-registry and mozart-vcs for request-level
observability (URL, status code, cache hits, download size).

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

1 files changed, 3 insertions, 0 deletions

diff --git a/crates/mozart-vcs/src/driver/gitlab.rs b/crates/mozart-vcs/src/driver/gitlab.rs
index 7b1a93b..f96c078 100644
--- a/crates/mozart-vcs/src/driver/gitlab.rs
+++ b/crates/mozart-vcs/src/driver/gitlab.rs
@@ -80,6 +80,7 @@ impl GitLabDriver {
         )
     }
 
+    #[tracing::instrument(skip(self))]
     async fn api_get(&self, path: &str) -> Result<serde_json::Value> {
         let url = self.api_url(path);
         let mut req = self
@@ -93,6 +94,7 @@ impl GitLabDriver {
         }
 
         let response = req.send().await?;
+        tracing::debug!(status = %response.status(), %url, "GitLab API response");
         if !response.status().is_success() {
             bail!(
                 "GitLab API request to {} failed with status {}",
@@ -103,6 +105,7 @@ impl GitLabDriver {
         Ok(response.json().await?)
     }
 
+    #[tracing::instrument(skip(self))]
     async fn api_get_paginated(&self, path: &str) -> Result<Vec<serde_json::Value>> {
         let mut items = Vec::new();
         let mut page = 1;