feat(sdk): variable declaration read apis + browser-safe variables entry (#2046)

packages/core/src/variables.ts

@@ -0,0 +1,32 @@
+/**
+ * Browser-safe variables entry (`@hyperframes/core/variables`) — the complete
+ * composition-variables surface in one import: schema types, the declaration
+ * parser, runtime value resolution, and value validation. Deliberately free of
+ * the Node-only modules reachable from the core/parsers root entries, so
+ * browser consumers (SDK, Studio, embedders) can bundle it.
+ */
+
+export type {
+  CompositionVariable,
+  CompositionVariableType,
+  CompositionVariableBase,
+  StringVariable,
+  NumberVariable,
+  ColorVariable,
+  BooleanVariable,
+  EnumVariable,
+  FontVariable,
+  ImageVariable,
+} from "@hyperframes/parsers/composition";
+export {
+  COMPOSITION_VARIABLE_TYPES,
+  parseCompositionVariables,
+  isScalarVariableValue,
+} from "@hyperframes/parsers/composition";
+
+export { getVariables, readDeclaredDefaults } from "./runtime/getVariables.js";
+export {
+  validateVariables,
+  formatVariableValidationIssue,
+  type VariableValidationIssue,
+} from "./runtime/validateVariables.js";