[TrimmableTypeMap] Close scanner and JCW generator gaps vs legacy pipeline

[simonrozsival]

Part of #10933. Stacked on #10924 (override detection PR).

Summary

Closes gaps between the new trimmable scanner/JCW generator and the legacy Cecil-based pipeline, discovered by building the samples/HelloWorld app and deep analysis against CecilImporter.

What we can now detect

Interface method implementations without [Register]

// User code — no [Register] on OnClick:publicclassMyListener:Java.Lang.Object,IOnClickListener{publicvoidOnClick(Viewv){}}

The scanner now iterates implemented interfaces and adds their [Register]'d methods to the implementing type's marshal methods.

[Export] method access modifiers

[Export("protectedMethod")]protectedvoidProtectedMethod(){}// JCW now correctly emits:// protected void protectedMethod () { ... }// Previously always emitted "public".

[ExportField] attributes

[ExportField("VALUE")]publicstringGetValue()=>"hello";// JCW now emits:// public java.lang.String VALUE = GetValue ();// public java.lang.String GetValue () { return n_GetValue (); }

Constructor super() fallback patterns

// User ctor params don't match base — falls back to super():publicCustomParamActivity(string title,int count){super(); ...}

Already worked correctly; now has test coverage.

Covariant return type overrides

// Base: [Register ("getResult", "()Ljava/lang/Object;")]// Override with narrower return — JCW uses base's JNI signature.publicoverrideJava.Lang.ObjectGetResult()=>myString;

Already worked correctly; now has test coverage.

Tests

245 unit tests pass (+4 new test files, 25 new test methods).

[simonrozsival]

Closing — all scanner/JCW gap fixes (interface method detection, export access modifiers, export fields, constructor super() fallback, covariant return types) have been folded into the base PR #10924.