[tsp] Adding empty project for the TypeSpec library. (#318)

This pull request introduces the initial setup for the new
`@alloy-js/typespec` package, including its configuration, dependencies,
and build/test scripts. The changes ensure the package is ready for
development, testing, and documentation generation, and integrate it
into the project’s monorepo structure.

**New package setup and configuration:**

* Added `packages/typespec/package.json` to define the package name,
exports/imports, scripts, dependencies, and devDependencies for
`@alloy-js/typespec`.
* Added `packages/typespec/tsconfig.json` to configure TypeScript
compilation settings, declaration output, project references, and file
inclusions/exclusions.
* Added `packages/typespec/api-extractor.json` to configure API
Extractor for documentation generation.
* Added `packages/typespec/vitest.config.ts` to set up Vitest testing
configuration and integrate the Alloy rollup plugin.

**Monorepo integration:**

* Updated `pnpm-lock.yaml` to register `@alloy-js/typespec` and its
dependencies in the workspace, ensuring proper package management and
linking.

Author: glecaros

.gitignore

@@ -142,4 +142,5 @@ packages/*/tsdoc-metadata.json
 packages/docs/src/content/docs/reference
 packages/docs/dist-build
 
-alloy-output/
+alloy-output/
+.pnpm-store/

packages/typespec/api-extractor.json

@@ -0,0 +1,4 @@
+{
+  "$schema": "https://developer.microsoft.com/json-schemas/api-extractor/v7/api-extractor.schema.json",
+  "extends": "../../api-extractor.base.json"
+}

packages/typespec/package.json

@@ -0,0 +1,51 @@
+{
+  "name": "@alloy-js/typespec",
+  "version": "0.1.0",
+  "description": "",
+  "exports": {
+    ".": {
+      "development": "./src/index.ts",
+      "import": "./dist/src/index.js"
+    },
+    "./stc": {
+      "development": "./src/components/stc/index.ts",
+      "import": "./dist/src/components/stc/index.js"
+    },
+    "./testing": {
+      "development": "./testing/index.ts",
+      "import": "./dist/testing/index.js"
+    }
+  },
+  "imports": {
+    "#components/*": {
+      "development": "./src/components/*",
+      "default": "./dist/src/components/*"
+    }
+  },
+  "scripts": {
+    "generate-docs": "api-extractor run",
+    "build": "alloy build && pnpm run generate-docs",
+    "clean": "rimraf dist/ .temp/",
+    "test:watch": "vitest -w",
+    "watch": "alloy build --watch",
+    "test": "vitest run",
+    "prepack": "node ../../scripts/strip-dev-exports.js"
+  },
+  "keywords": [],
+  "license": "MIT",
+  "dependencies": {
+    "@alloy-js/core": "workspace:~",
+    "change-case": "catalog:",
+    "pathe": "catalog:"
+  },
+  "devDependencies": {
+    "@alloy-js/cli": "workspace:~",
+    "@alloy-js/rollup-plugin": "workspace:~",
+    "@microsoft/api-extractor": "catalog:",
+    "@rollup/plugin-typescript": "catalog:",
+    "concurrently": "catalog:",
+    "typescript": "catalog:",
+    "vitest": "catalog:"
+  },
+  "type": "module"
+}

packages/typespec/src/index.ts

@@ -0,0 +1,19 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "compilerOptions": {
+    "emitDeclarationOnly": true,
+    "declaration": true,
+    "outDir": "dist",
+    "types": ["@alloy-js/core/testing/matchers"]
+  },
+  "references": [{ "path": "../core" }],
+  "include": [
+    "src/**/*.ts",
+    "src/**/*.tsx",
+    "test/**/*.ts",
+    "test/**/*.tsx",
+    "testing/**/*.ts",
+    "testing/**/*.tsx"
+  ],
+  "exclude": ["node_modules", "dist"]
+}

packages/typespec/tsconfig.json

@@ -0,0 +1,10 @@
+import alloyPlugin from "@alloy-js/rollup-plugin";
+import { defineConfig } from "vitest/config";
+
+export default defineConfig({
+  esbuild: {
+    jsx: "preserve",
+    sourcemap: "both",
+  },
+  plugins: [alloyPlugin()],
+});