refactor: consolidate recipeError

[lifeizhou-ap]

Summary

Why
When user runs Goose CLI, when there is some error in template, it will show error message

Error: Template rendering failed: syntax error: unknown statement ifw (in recipe_template:168)

This is not intuitive to user because templating is the implementation details and is not intuitive to some users.

What

• Consolidate the RecipeParsing and TemplateRendering Error in Recipe Error to Invalid Error and provide better message
• rename the internal template name to recipe

After change, the error message is

Error: Invalid recipe: syntax error: unknown statement ifw (in recipe:168)

Type of Change

• Feature
• Bug fix
• Refactor / Code quality
• Performance improvement
• Documentation
• Tests
• Security fix
• Build / Release
• Other (specify below)

AI Assistance

• This PR was created or reviewed with AI assistance

Testing

Unit test

[Copilot]

Pull request overview

This PR consolidates recipe error types to improve user-facing error messages by hiding implementation details. It merges RecipeError::TemplateRendering and RecipeError::RecipeParsing into a single RecipeError::Invalid variant, and renames the internal template name from "recipe_template" to "recipe".

Changes:

• Consolidated two error variants (TemplateRendering and RecipeParsing) into a single Invalid variant for clearer error messages
• Renamed internal template name constant from "recipe_template" to "recipe" to improve error message readability
• Updated all test cases to match the new error variant

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
crates/goose/src/recipe/template_recipe.rs	Changed CURRENT_TEMPLATE_NAME from "recipe_template" to "recipe" for better error messages
crates/goose/src/recipe/build_recipe/mod.rs	Consolidated TemplateRendering and RecipeParsing error variants into single Invalid variant
crates/goose/src/recipe/build_recipe/tests.rs	Updated all test assertions to expect RecipeError::Invalid instead of the old variants

[zanesq]

LGTM!