chore(auth): also mention that atproto spec requiers typ be "JWT" for inter-service tokens

Cargo.lock

@@ -7837,6 +7837,7 @@ dependencies = [
  "sha2",
  "sqlx",
  "subtle",
+ "tempfile",
  "testcontainers",
  "testcontainers-modules",
  "thiserror 2.0.18",

crates/tranquil-auth/src/types.rs

@@ -16,6 +16,7 @@ impl TokenType {
             Self::Access => "at+jwt",
             Self::Refresh => "refresh+jwt",
             // RFC 7519 §5.1 recommends the uppercase "JWT".
+            // and for atproto inter-service auth its a requirement.
             Self::Service => "JWT",
         }
     }