chore: release version 15.2.1-alpha.0 for igniteui-cli and related packages

- Updated version to 15.2.1-alpha.0 in igniteui-cli, cli-core, and mcp-server packages.
- Updated dependencies in igniteui-cli and igx-templates to use the new alpha version.
- Enhanced CHANGELOG.md with notable changes for version 15.2.1-alpha.0, including bug fixes and feature updates.
- Adjusted package.json files for angular-templates and angular-schematics to reflect new versioning.

Author: dkalinovInfra

.github/workflows/npm-publish.yml

@@ -24,6 +24,10 @@ jobs:
       - name: Install packages
         run: yarn install --frozen-lockfile
 
+      - name: Build MCP API docs
+        working-directory: packages/igniteui-mcp/igniteui-doc-mcp
+        run: npm run build:docs:all
+
       - name: Build packages
         run: |
           npm run build-pack