feat(backend): Add 'method' type annotation support for PyBuilder

common/pybuilder/src/main/scala/org/apache/texera/amber/pybuilder/EncodableInspector.scala

@@ -46,7 +46,7 @@ final class EncodableInspector[C <: blackbox.Context](val c: C) {
 
   // Keep this as a string so it also works if the annotation is referenced indirectly.
   private val encodableStringAnnotationFqn =
-    "org.apache.texera.amber.EncodableStringAnn"
+    "org.apache.texera.amber.pybuilder.EncodableStringAnnotation"
 
   /**
    * If we are pointing at a getter/accessor, hop to its accessed field symbol when possible.
@@ -110,10 +110,20 @@ final class EncodableInspector[C <: blackbox.Context](val c: C) {
     val symHasAnn =
       rawSym != null && rawSym != NoSymbol && {
         val accessed = safeAccessed(rawSym)
-        accessed != null && accessed != NoSymbol && accessed.annotations.exists(annIsEncodableString)
+        accessed != null && accessed != NoSymbol &&
+          accessed.annotations.exists(annIsEncodableString)
       }
 
-    symHasAnn || (tree.tpe != null && typeHasEncodableString(tree.tpe))
+    val methodReturnHasAnn =
+      rawSym != null && rawSym != NoSymbol && (rawSym match {
+        case m: MethodSymbol =>
+          typeHasEncodableString(m.typeSignature.finalResultType)
+        case _ =>
+          false
+      })
+
+    symHasAnn || methodReturnHasAnn ||
+      (tree.tpe != null && typeHasEncodableString(tree.tpe))
   }
 
   def isPythonTemplateBuilderArg(argExpr: c.Expr[Any]): Boolean = {

common/pybuilder/src/main/scala/org/apache/texera/amber/pybuilder/EncodableStringAnnotation.java

@@ -29,6 +29,7 @@
     ElementType.FIELD,
     ElementType.PARAMETER,
     ElementType.TYPE_USE,
-    ElementType.LOCAL_VARIABLE
+    ElementType.LOCAL_VARIABLE,
+    ElementType.METHOD
 })
 public @interface EncodableStringAnnotation {}

common/pybuilder/src/test/scala/org/apache/texera/amber/pybuilder/PythonTemplateBuilderSpec.scala

@@ -275,6 +275,22 @@ class PythonTemplateBuilderSpec extends AnyFunSuite {
     assert(builder.encode == "param-only")
   }
 
+  test("@StringUI method annotation triggers UI encoding") {
+    object Holder {
+      @EncodableStringAnnotation def uiText: String = "method"
+    }
+    val builder = pyb"${Holder.uiText}"
+    assert(builder.encode == decodeExpr("method"))
+  }
+
+  test("@StringUI method annotation on def with parens triggers UI encoding") {
+    object Holder {
+      @EncodableStringAnnotation def uiText(): String = "method-parens"
+    }
+    val builder = pyb"${Holder.uiText()}"
+    assert(builder.encode == decodeExpr("method-parens"))
+  }
+
   test("unannotated String does not become UI (stays raw python)") {
     val rawText: String = "raw"
     val builder = pyb"$rawText"