fix: lower log level for missing base ref on main/master builds (EME-369)

Changes the logging level from warn to info when failing to detect base
branch reference on main/master branch builds. This reduces noise in
build logs for these common scenarios while maintaining warn level for
other branches where missing base ref may indicate configuration issues.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: runningcode

src/commands/build/upload.rs

@@ -192,7 +192,14 @@ pub fn execute(matches: &ArgMatches) -> Result<()> {
                             Some(base_ref_name)
                         }
                         Err(e) => {
-                            warn!("Could not detect base branch reference: {}", e);
+                            // Lower log level for main/master branch builds
+                            if head_ref.as_deref() == Some("main")
+                                || head_ref.as_deref() == Some("master")
+                            {
+                                info!("Could not detect base branch reference: {}", e);
+                            } else {
+                                warn!("Could not detect base branch reference: {}", e);
+                            }
                             None
                         }
                     })