fix: refactor projectwriter to receive immutable project name mappings

[cdsap]

Summary

Problem

ProjectWriter reads layer and module names from the mutable global NameMappings singleton instead of receiving them as an explicit dependency. ProjectGenerator configures this global state before writing, while ProjectWriterTest mutates and restores it manually.

Why this matters

The writer's output depends on hidden process-wide state, which couples generation runs, complicates parallel execution, and makes unit tests order-sensitive. The repository already has ProjectNameMaps as an immutable value object.

Proposed change

Add a ProjectNameMaps parameter to ProjectWriter and use it when rendering settings.gradle files. Pass the maps created by ProjectNameMappingFactory from ProjectGenerator, and update ProjectWriter tests to provide explicit maps instead of mutating NameMappings.

Notes

ProjectNameMaps acts as a domain value object, while ProjectWriter is an output adapter. Making the mapping dependency explicit clarifies that boundary and improves testability without changing the wider generation architecture.

Fixes #470

Changes

• project-generator/src/main/kotlin/io/github/cdsap/projectgenerator/ProjectGenerator.kt
• project-generator/src/main/kotlin/io/github/cdsap/projectgenerator/writer/ProjectWriter.kt
• project-generator/src/test/kotlin/io/github/cdsap/projectgenerator/generator/buildfiles/BuildFilesGeneratorAndroidTest.kt
• project-generator/src/test/kotlin/io/github/cdsap/projectgenerator/generator/buildfiles/BuildFilesGeneratorJvmTest.kt
• project-generator/src/test/kotlin/io/github/cdsap/projectgenerator/generator/test/TestGeneratorAndroidTest.kt
• project-generator/src/test/kotlin/io/github/cdsap/projectgenerator/generator/test/TestGeneratorJvmTest.kt
• project-generator/src/test/kotlin/io/github/cdsap/projectgenerator/writer/ProjectWriterTest.kt

Verification

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