fix(core): Migrate file I/O to @push.rocks/smartfs, adopt TC39 decorators v3 accessor in web components, and update docs/tests

readme.hints.md

@@ -1 +1,40 @@
- 
+# Development Hints
+
+## Dependencies (v2.0.0)
+
+- Uses `@push.rocks/smartfs` (v1.2.0) for filesystem operations - SmartFs is class-based with fluent API
+- Uses `@push.rocks/smartfile` (v13.1.0) - note: v13 removed the `.fs` namespace, use smartfs instead
+- Uses `@git.zone/tstest/tapbundle` for tests (NOT @push.rocks/tapbundle)
+- Test files must end with `export default tap.start()`
+
+## TC39 Decorators v3
+
+All decorated properties in web components use the `accessor` keyword:
+```typescript
+@property({ type: Object })
+accessor letterData: TInvoice;
+```
+
+## SmartFs Usage
+
+```typescript
+import { SmartFs, SmartFsProviderNode } from '@push.rocks/smartfs';
+const smartfs = new SmartFs(new SmartFsProviderNode());
+
+// Reading files
+await smartfs.file('/path/to/file').encoding('utf8').read();
+
+// Writing files
+await smartfs.file('/path/to/file').write(buffer);
+
+// Directory operations
+await smartfs.directory('/path').exists();
+await smartfs.directory('/path').create();
+```
+
+## Project Structure
+
+- `ts/` - Node.js server-side code (PdfService)
+- `ts_web/` - Browser web components (Lit-based)
+- `ts_shared/` - Shared code (translations, interfaces)
+- `test/` - Test files