Migrate from Yarn to npm: add package-lock.json, remove yarn.lock, update CI and build pipelines

Co-authored-by: rzhao271 <7199958+rzhao271@users.noreply.github.com>

Author: Copilot

.github/workflows/ci.yml

@@ -12,5 +12,5 @@ jobs:
     - uses: actions/setup-node@v1
       with:
         node-version: ${{ matrix.node-version }}
-    - run: yarn install --frozen-lockfile
-    - run: yarn test
+    - run: npm ci
+    - run: npm test

build/pre-release.yml

@@ -15,10 +15,10 @@ extends:
   template: azure-pipelines/extension/pre-release.yml@templates
   parameters:
     buildSteps:
-      - script: yarn install --frozen-lockfile
+      - script: npm ci
         displayName: Install dependencies
 
-      - script: yarn run test
+      - script: npm test
         displayName: Typecheck extension
 
     tsa:

build/stable.yml

@@ -24,10 +24,10 @@ extends:
   template: azure-pipelines/extension/stable.yml@templates
   parameters:
     buildSteps:
-      - script: yarn install --frozen-lockfile
+      - script: npm ci
         displayName: Install dependencies
 
-      - script: yarn run test
+      - script: npm test
         displayName: Typecheck extension
 
     tsa: