fix: refactor generated module paths to a shared layout helper

[cdsap]

Summary

Problem

Generated module filesystem paths are assembled independently in several generation/writer classes: ModulesWriter.kt:71-83 creates source/test directories, ResourceGenerator.kt:34-39 and 74-85 creates resource/manifest paths, ClassGeneratorAndroid.kt:752-760 writes class paths, and TestGeneratorAndroid.kt:25-33 writes test paths. Each repeats layer/module/package lookup plus string-concatenated source-set paths.

Why this matters

Android KMP source-set behavior already depends on module type and kotlinMultiplatformLibrary. Keeping that path policy duplicated makes future layout changes easy to apply inconsistently, especially between pre-created directories, generated classes, tests, resources, and manifests.

Proposed change

Introduce one small core/project-generator helper, for example GeneratedModuleLayout, that takes projectName, ProjectGraph or module metadata, and kotlinMultiplatformLibrary, then exposes File builders for main Kotlin package, test Kotlin package, resources layout/values, and manifest directory. Migrate the Android generation call sites to use it without changing generated paths or file contents.

Notes

Clean architecture lens: this keeps generated-project layout policy in one domain-level helper instead of scattering infrastructure path strings through content generators and writers.

Fixes #426

Changes

• project-generator/src/main/kotlin/io/github/cdsap/projectgenerator/generator/GeneratedModuleLayout.kt
• project-generator/src/main/kotlin/io/github/cdsap/projectgenerator/generator/classes/ClassGeneratorAndroid.kt
• project-generator/src/main/kotlin/io/github/cdsap/projectgenerator/generator/resources/ResourceGenerator.kt
• project-generator/src/main/kotlin/io/github/cdsap/projectgenerator/generator/test/TestGeneratorAndroid.kt
• project-generator/src/main/kotlin/io/github/cdsap/projectgenerator/writer/ModulesWriter.kt
• project-generator/src/test/kotlin/io/github/cdsap/projectgenerator/generator/GeneratedModuleLayoutTest.kt

Verification

• ./gradlew :project-generator:unitTest
• ./gradlew :cli:test
• ./gradlew ktlintCheck