vm/router: minimal special-method extension (equals/1); toString mapping kept

mir: add TypeCertainty to Callee::Method (diagnostic only); plumb through builder/JSON/printer; backends ignore behaviorally

using: confirm unified prelude resolver entry for all runner modes

docs: update Callee architecture with certainty; update call-instructions; CURRENT_TASK note

tests: quick 40/40 PASS; integration (LLVM) 17/17 PASS

src/mir/builder/calls/method_resolution.rs

@@ -32,6 +32,7 @@ pub fn resolve_call_target(
                 box_name: box_name.clone(),
                 method: name.to_string(),
                 receiver: None, // Static method call
+                certainty: crate::mir::definitions::call_unified::TypeCertainty::Known,
             });
         }
     }