refactor: use eq_ignore_ascii_case instead of to_ascii_lowercase

Avoids per-header String allocation in the loop. Consistent with
get_part_header in the same file.

Addresses gemini-code-assist review feedback.

Author: gura105

crates/google-workspace-cli/src/helpers/gmail/mod.rs

@@ -258,15 +258,23 @@ fn parse_message_headers(headers: &[Value]) -> ParsedMessageHeaders {
         let name = header.get("name").and_then(|v| v.as_str()).unwrap_or("");
         let value = header.get("value").and_then(|v| v.as_str()).unwrap_or("");
 
-        match name.to_ascii_lowercase().as_str() {
-            "from" => parsed.from = value.to_string(),
-            "reply-to" => append_address_list_header_value(&mut parsed.reply_to, value),
-            "to" => append_address_list_header_value(&mut parsed.to, value),
-            "cc" => append_address_list_header_value(&mut parsed.cc, value),
-            "subject" => parsed.subject = value.to_string(),
-            "date" => parsed.date = value.to_string(),
-            "message-id" => parsed.message_id = value.to_string(),
-            "references" => append_header_value(&mut parsed.references, value),
+        match name {
+            s if s.eq_ignore_ascii_case("from") => parsed.from = value.to_string(),
+            s if s.eq_ignore_ascii_case("reply-to") => {
+                append_address_list_header_value(&mut parsed.reply_to, value)
+            }
+            s if s.eq_ignore_ascii_case("to") => {
+                append_address_list_header_value(&mut parsed.to, value)
+            }
+            s if s.eq_ignore_ascii_case("cc") => {
+                append_address_list_header_value(&mut parsed.cc, value)
+            }
+            s if s.eq_ignore_ascii_case("subject") => parsed.subject = value.to_string(),
+            s if s.eq_ignore_ascii_case("date") => parsed.date = value.to_string(),
+            s if s.eq_ignore_ascii_case("message-id") => parsed.message_id = value.to_string(),
+            s if s.eq_ignore_ascii_case("references") => {
+                append_header_value(&mut parsed.references, value)
+            }
             _ => {}
         }
     }