feat: add Blazor project scaffolding options and templates

[dkalinovInfra]

Description

Adds first-class Blazor project scaffolding to the CLI. The Blazor framework is now visible in both the ig new command and the Step-By-Step wizard, and projects are generated via the published IgniteUI.Blazor.Templates NuGet template package using the dotnet CLI rather than the Handlebars template pipeline.

Key changes:

• New scaffold() strategy on ProjectTemplate — when a project template implements the optional scaffold(options: ScaffoldOptions) method, the host calls it instead of the generateConfig → processTemplates → installPackages pipeline. This lets a project delegate generation to an external tool while still participating in AI/agent configuration and git init.
• DotnetTemplateManager (new, in @igniteui/cli-core) — a thin wrapper around the dotnet CLI that verifies the .NET SDK (8+) is present, installs the IgniteUI.Blazor.Templates package if missing, and runs dotnet new igb-blazor with the chosen hosting model, theme, and variant. All failures are reported and returned as false (no throwing).
• New "Blazor Web App" project template (blazor/igb/projects/empty) — exposes extra configuration for the Hosting model (Server / Wasm / Auto) and theme Variant (light / dark), and forwards everything to DotnetTemplateManager.scaffold().
• ig new options — added --hosting (Server|Wasm|Auto) and --variant (light|dark) flags for Blazor projects, name-validation warning for non-identifier project names, and Blazor-specific "Next Steps" output.
• Wizard support (BasePromptSession) — runs extra-configuration prompts and the scaffold() path for scaffold-based templates, handles git init (since the scaffold service never touches git), and prints dotnet run next-steps / optional run prompt for projects with no cli-config.
• Misc — Blazor igb themes changed from ["default"] to ["bootstrap", "material", "fluent", "indigo"]; Blazor framework un-hidden; Util.spawnSync now allows dotnet as a known binary; customizeTemplateTask accepts BaseTemplate.

Related Issue

Closes #

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Refactoring / code cleanup
• Build / CI configuration change

Affected Packages

• igniteui-cli (packages/cli)
• @igniteui/cli-core (packages/core)
• @igniteui/angular-templates (packages/igx-templates)
• @igniteui/angular-schematics (packages/ng-schematics)
• @igniteui/mcp-server (packages/igniteui-mcp)

Checklist

• I have tested my changes locally (npm run test)
• I have built the project successfully (npm run build)
• I have run the linter (npm run lint)
• I have added/updated tests as needed
• My changes do not introduce new warnings or errors

Additional Context

New/updated test coverage:

• spec/unit/DotnetTemplateManager-spec.ts — SDK detection, template install, and scaffold argument/error handling.
• spec/unit/PromptSession-spec.ts — wizard scaffold path and next-steps behavior.
• spec/unit/new-spec.ts — ig new Blazor options and scaffold invocation.
• spec/templates/blazor-spec.ts, spec/unit/Util-spec.ts, spec/acceptance/help-spec.ts — template metadata, spawnSync binary allow-list, and updated help output.

Example usage:

ig new MyApp --framework blazor --type igb --hosting Server --theme bootstrap --variant dark
cd MyApp
dotnet run --project MyApp

[Copilot]

Pull request overview

Adds first-class Blazor project scaffolding support to the Ignite UI CLI by introducing a scaffold()-based generation path (delegating project creation to dotnet new via a new DotnetTemplateManager) and wiring this through both ig new and the Step-By-Step wizard, along with new Blazor templates/options and updated tests.

Changes:

• Introduces ProjectTemplate.scaffold(options) + ScaffoldOptions and a DotnetTemplateManager wrapper to generate Blazor projects via dotnet new igb-blazor.
• Adds a new visible “Blazor Web App” (igb) project template and exposes Blazor in CLI help + wizard flows, including Blazor-specific options (hosting/variant) and next-steps output.
• Expands unit/acceptance/template tests to cover the new scaffold path, Blazor metadata, help output, and dotnet allow-listing.

Reviewed changes

Copilot reviewed 17 out of 17 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
spec/unit/Util-spec.ts	Adds a compile-time test ensuring dotnet is allowed by Util.spawnSync typing.
spec/unit/PromptSession-spec.ts	Adds wizard tests for scaffold path + dotnet next-steps behavior.
spec/unit/new-spec.ts	Adds ig new tests verifying scaffold invocation, extraConfig handling, and next-steps output.
spec/unit/DotnetTemplateManager-spec.ts	Adds unit coverage for SDK detection, template install, and scaffold argument/error handling.
spec/templates/blazor-spec.ts	Ensures Blazor framework visibility, theme list, and empty scaffold template registration.
spec/acceptance/help-spec.ts	Updates help output expectations to include Blazor and new flags.
packages/core/util/Util.ts	Allows dotnet as a permitted binary for spawnSync and updates doc comment.
packages/core/util/index.ts	Re-exports DotnetTemplateManager from the util barrel.
packages/core/util/DotnetTemplateManager.ts	Implements dotnet-based scaffolding (SDK check, template install, dotnet new).
packages/core/types/ProjectTemplate.ts	Adds ScaffoldOptions and optional ProjectTemplate.scaffold() API.
packages/core/templates/BaseTemplateManager.ts	Updates framework-name filtering comment (hidden frameworks behavior).
packages/core/prompt/BasePromptSession.ts	Adds scaffold-based project generation path + Blazor “Complete & Run” handling.
packages/cli/templates/blazor/index.ts	Un-hides the Blazor framework in template metadata.
packages/cli/templates/blazor/igb/projects/empty/index.ts	Adds “Blazor Web App” template that scaffolds via DotnetTemplateManager.
packages/cli/templates/blazor/igb/index.ts	Updates Blazor igb theme list to bootstrap/material/fluent/indigo.
packages/cli/lib/commands/types.ts	Adds hosting and variant args for the new command typing.
packages/cli/lib/commands/new.ts	Adds --hosting/--variant options and routes scaffold templates through scaffold() + dotnet next-steps.

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