feat: add Angular workspace with demo app and library build

- Restructure into standard Angular library workspace
- Library source in projects/ngx-pretext-table/
- Demo app in src/ using PretextVirtualScrollDirective
- Switch @chenglou/pretext dependency to npm registry (^0.0.4)
- Fix moduleResolution to "bundler" for Angular 17 compatibility

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tsconfig.json

@@ -0,0 +1,31 @@
+{
+  "compileOnSave": false,
+  "compilerOptions": {
+    "outDir": "./dist/out-tsc",
+    "strict": true,
+    "noImplicitOverride": true,
+    "noPropertyAccessFromIndexSignature": true,
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": true,
+    "skipLibCheck": true,
+    "paths": {
+      "ngx-pretext-table": ["./dist/ngx-pretext-table"]
+    },
+    "esModuleInterop": true,
+    "sourceMap": true,
+    "declaration": false,
+    "experimentalDecorators": true,
+    "moduleResolution": "bundler",
+    "importHelpers": true,
+    "target": "ES2022",
+    "module": "ES2022",
+    "useDefineForClassFields": false,
+    "lib": ["ES2022", "dom"]
+  },
+  "angularCompilerOptions": {
+    "enableI18nLegacyMessageIdFormat": false,
+    "strictInjectionParameters": true,
+    "strictInputAccessModifiers": true,
+    "strictTemplates": true
+  }
+}