feat: Merge isohash functionality into smarthash for cross-environment hash support

- Updated test files to use new tapbundle import from @git.zone/tstest.
- Created a new plan for merging isohash into smarthash, detailing objectives and implementation steps.
- Added browser-specific tests for SHA256 hashing functions in test/test.browser.ts.
- Implemented browser-compatible hashing functions in ts_web/index.ts using Web Crypto API.
- Introduced plugins for environment detection and JSON handling in ts_web/plugins.ts.
- Ensured that existing smarthash functionality remains intact and consistent across environments.

ts_web/index.ts

@@ -0,0 +1,84 @@
+import * as plugins from './plugins.js';
+
+/**
+ * Convert ArrayBuffer to hex string
+ */
+const hex = (buffer: ArrayBuffer): string => {
+  const hexCodes: string[] = [];
+  const view = new DataView(buffer);
+  for (let i = 0; i < view.byteLength; i += 4) {
+    // Using getUint32 reduces the number of iterations needed (we process 4 bytes each time)
+    const value = view.getUint32(i);
+    // toString(16) will give the hex representation of the number without padding
+    const stringValue = value.toString(16);
+    // We use concatenation and slice for padding
+    const padding = '00000000';
+    const paddedValue = (padding + stringValue).slice(-padding.length);
+    hexCodes.push(paddedValue);
+  }
+
+  // Join all the hex strings into one
+  return hexCodes.join("");
+};
+
+/**
+ * Computes sha256 Hash from String
+ */
+export const sha256FromString = async (stringArg: string): Promise<string> => {
+  // Get the string as arraybuffer.
+  const buffer = (new TextEncoder()).encode(stringArg);
+  const hash = await crypto.subtle.digest("SHA-256", buffer);
+  const result = hex(hash);
+  return result;
+};
+
+/**
+ * Computes sha256 Hash from String synchronously
+ * Note: In browser environment, this is still async internally but we maintain the API
+ */
+export const sha256FromStringSync = (stringArg: string): string => {
+  console.warn('sha256FromStringSync is not truly synchronous in browser environment');
+  throw new Error('sha256FromStringSync is not supported in browser environment. Use sha256FromString instead.');
+};
+
+/**
+ * Computes sha256 Hash from ArrayBuffer
+ */
+export const sha256FromBuffer = async (bufferArg: ArrayBuffer | Uint8Array): Promise<string> => {
+  const hash = await crypto.subtle.digest("SHA-256", bufferArg);
+  const result = hex(hash);
+  return result;
+};
+
+/**
+ * computes sha265 Hash from Object
+ */
+export const sha265FromObject = async (objectArg: any): Promise<string> => {
+  const stringifiedObject = plugins.smartjson.stringify(objectArg);
+  const hashResult = await sha256FromString(stringifiedObject);
+  return hashResult;
+};
+
+/**
+ * creates sha256 Hash from Stream
+ * Note: Not supported in browser environment
+ */
+export const sha256FromStream = (input: any): Promise<string> => {
+  throw new Error('sha256FromStream is not supported in browser environment');
+};
+
+/**
+ * creates sha256 Hash from File
+ * Note: Not supported in browser environment
+ */
+export const sha256FromFile = async (filePath: string): Promise<string> => {
+  throw new Error('sha256FromFile is not supported in browser environment');
+};
+
+/**
+ * Computes MD5 Hash from String
+ * Note: MD5 is not natively supported by Web Crypto API
+ */
+export const md5FromString = async (stringToHash: string): Promise<string> => {
+  throw new Error('md5FromString is not supported in browser environment. Web Crypto API does not support MD5.');
+};