Restructure frontend code to allow for extensions (#4721)

# Description of Changes
Move frontend code into `core` folder and add infrastructure for
`proprietary` folder to include premium, non-OSS features

frontend/src/core/hooks/useToolParameters.ts

@@ -0,0 +1,51 @@
+/**
+ * React hooks for tool parameter management (URL logic removed)
+ */
+
+import { useCallback, useMemo } from 'react';
+
+type ToolParameterValues = Record<string, any>;
+
+/**
+ * Register tool parameters and get current values
+ */
+export function useToolParameters(
+  _toolName: string,
+  _parameters: Record<string, any>
+): [ToolParameterValues, (updates: Partial<ToolParameterValues>) => void] {
+
+  // Return empty values and noop updater
+  const currentValues = useMemo(() => ({}), []);
+  const updateParameters = useCallback(() => {}, []);
+
+  return [currentValues, updateParameters];
+}
+
+/**
+ * Hook for managing a single tool parameter
+ */
+export function useToolParameter<T = any>(
+  toolName: string,
+  paramName: string,
+  definition: any
+): [T, (value: T) => void] {
+  const [allParams, updateParams] = useToolParameters(toolName, { [paramName]: definition });
+
+  const value = allParams[paramName] as T;
+
+  const setValue = useCallback((newValue: T) => {
+    updateParams({ [paramName]: newValue });
+  }, [paramName, updateParams]);
+
+  return [value, setValue];
+}
+
+/**
+ * Hook for getting/setting global parameters (zoom, page, etc.)
+ */
+export function useGlobalParameters() {
+  const currentValues = useMemo(() => ({}), []);
+  const updateParameters = useCallback(() => {}, []);
+
+  return [currentValues, updateParameters];
+}