runner: centralize resolve env flags

src/config/env/using_flags.rs

@@ -3,6 +3,7 @@
 //! This module groups all `using` system and namespace flags.
 //! Use this for IDE autocomplete to discover using/namespace flags easily.
 
+use super::env_bool;
 use super::warn_alias_once;
 
 pub fn enable_using() -> bool {
@@ -68,3 +69,18 @@ pub fn using_ast_enabled() -> bool {
         _ => !using_is_prod(), // dev/ci → true, prod → false
     }
 }
+
+// ---- Using/resolve diagnostics ----
+pub fn resolve_trace() -> bool {
+    env_bool("NYASH_RESOLVE_TRACE")
+}
+
+pub fn resolve_seam_debug() -> bool {
+    env_bool("NYASH_RESOLVE_SEAM_DEBUG")
+}
+
+pub fn resolve_dump_merged_path() -> Option<String> {
+    std::env::var("NYASH_RESOLVE_DUMP_MERGED")
+        .ok()
+        .filter(|s| !s.is_empty())
+}