feat: allow multiple input dir

[fs-eire]

Introduce functionality to load templates from multiple directories.

[fs-eire]

@daijh FYI

[Copilot]

Pull Request Overview

This PR extends template loading and building to support multiple source directories with optional aliases.

• Adds loadFromDirectories to the loader with alias and conflict detection
• Updates build API and runner to accept multiple sourceDirs instead of a single sourceDir
• Expands test types and test runners to cover "loader-directories" scenarios

Reviewed Changes

Copilot reviewed 30 out of 36 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/types.ts	Extended Loader and BuildOptions to use multiple directories
src/loader-impl.ts	Implemented loadFromDirectories and alias support
src/index.ts	Replaced sourceDir with sourceDirs in build API
test/test-types.ts	Added LoaderDirectoriesTestConfig and sourceDirs
test/test-runner-loader.ts	Added runLoaderDirectoriesTest handler
test/test-runner-build.ts	Updated runBuildTest to map and validate sourceDirs
test/test-main.ts	Registered the "loader-directories" test runner
test/testcases/...	New and updated test fixtures for multi-directory loader

Comments suppressed due to low confidence (2)

src/index.ts:34

• Changing the public API from a single sourceDir to sourceDirs is a breaking change. Consider providing an overload or deprecating sourceDir before removing it to maintain backward compatibility.

  sourceDirs: ({ path: string; alias?: string } | string)[];

test/testcases/build-directories/src/effects/blur.wgsl.template:3

• The code calls textureSample with samp, but no sampler parameter named samp is defined in this function. Consider adding a sampler argument or correcting the variable name.

    return textureSample(tex, samp, uv);

[Copilot]

[nitpick] This conditional always picks the first directory even when multiple are provided. Either simplify the expression or clarify how basePath should be determined when loading from multiple directories.

Suggested change

	// Use the first directory as the base path for simplicity
	const basePath = resolvedBasePaths.length === 1 ? resolvedBasePaths[0] : resolvedBasePaths[0]; // For multiple directories, use the first one as base
	// Determine the base path: use the common base directory for multiple directories
	const basePath = resolvedBasePaths.length === 1
	? resolvedBasePaths[0]
	: path.dirname(path.common(...resolvedBasePaths)); // Compute common base directory