add total build time to verbose output, harden dispatchNamedObject (#497)

`chad build -v foo.ts` now appends " in Xms" to the "Compiled: ..." line.
Useful when something feels slow and you want to know without reaching
for the shell's `time`. No behavior change at default verbosity.

The one-line `return null;` added to `MethodCallGenerator.dispatchNamedObject`
after the switch-with-default is a workaround for a native-compiler false
positive in checkMissingReturns: any edit to compileNative's body shifts
AST layout enough to trip it on dispatchNamedObject. The extra trailing
return makes the function immune. Node compiler accepts the original code
fine; this only affects the self-hosted path.

Co-authored-by: cs01 <cs01@users.noreply.github.com>

Author: cs01

src/codegen/expressions/method-calls.ts

@@ -436,6 +436,7 @@ export class MethodCallGenerator {
       default:
         return null;
     }
+    return null;
   }
 
   private handleYamlParse(expr: MethodCallNode, params: string[]): string {

src/native-compiler-lib.ts

@@ -430,6 +430,7 @@ export function parseFileToAST(inputFile: string): string {
 }
 
 export function compileNative(inputFile: string, outputFile: string): void {
+  const phaseStart = Date.now();
   const execDir = path.dirname(path.resolve(process.argv0));
   const installedLibDir = execDir + "/lib";
   const isInstalled = fs.existsSync(installedLibDir + "/libgc.a");
@@ -939,7 +940,7 @@ export function compileNative(inputFile: string, outputFile: string): void {
 
   fs.unlinkSync(objFile);
   if (verbose) {
-    console.log("Compiled: " + outputFile);
+    console.log("Compiled: " + outputFile + " in " + (Date.now() - phaseStart) + "ms");
   }
 }