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.

readme.plan.md

@@ -0,0 +1,40 @@
+# Merge Plan: isohash into smarthash
+
+**First line: Command to reread CLAUDE.md**: `cat ~/.claude/CLAUDE.md`
+
+## Objective
+Merge the functionality from @push.rocks/isohash into @push.rocks/smarthash to provide cross-environment hash support (browser and Node.js).
+
+## Implementation Steps
+
+### 1. Create ts_web directory structure ✓
+- Create `./ts_web` directory for browser-specific code
+- This will house the Web Crypto API implementation
+
+### 2. Add required dependencies ✓
+- Add `@push.rocks/smartenv` to package.json dependencies
+- This is needed for environment detection
+
+### 3. Create web-specific plugin file ✓
+- Create `ts_web/plugins.ts` with smartenv import
+- Follow the plugins pattern used in the Node.js version
+
+### 4. Implement browser-compatible hash functions ✓
+- Copy and adapt `index.ts` from isohash to `ts_web/index.ts`
+- Remove circular dependency (isohash importing smarthash)
+- Use native Web Crypto API for SHA256 in browser
+- Maintain compatibility with existing smarthash API
+
+### 5. Build and verify ✓
+- Run `pnpm build` to ensure TypeScript compilation succeeds
+- Check that both Node.js and browser builds are created
+
+### 6. Test functionality ✓
+- Run `pnpm test` to ensure all tests pass
+- Verify browser compatibility through web tests
+
+## Key Considerations
+- The web version uses native Web Crypto API for performance
+- The Node.js version continues using the existing crypto implementation
+- API remains consistent across both environments
+- No breaking changes to existing smarthash functionality