fix: refactor android feature validation to isolate cli errors from requ

[cdsap]

Summary

Problem

cli/src/main/kotlin/io/github/cdsap/projectgenerator/cli/GenerateProjectRequest.kt:3 imports Clikt UsageError, and validateAndroidOnlyFeatures at lines 96-106 throws CLI-framework exceptions from the request-resolution code used by GenerateProjectRequest.resolve at lines 47-92. Main.kt lines 57-81 is the actual Clikt command boundary, while GenerateProjectRequest also resolves project name, Gradle version, output path, Develocity enablement, and versions overrides. Tests in cli/src/test/kotlin/io/github/cdsap/projectgenerator/cli/GenerateProjectsCliTest.kt:52-108 assert UsageError directly from GenerateProjectRequest.resolve, so the framework coupling is now part of lower-level resolver behavior.

Why this matters

The request resolver is close to an application/service boundary: it turns parsed inputs into a ProjectGenerator request. Having it construct Clikt exceptions makes that behavior harder to reuse from another adapter, such as the backend or tests that want pure request validation, and forces non-CLI logic to depend on CLI presentation concerns.

Proposed change

Introduce a tiny CLI-domain validation result for Android-only feature compatibility, for example an internal ProjectFeatureCompatibility or GenerateProjectRequestValidation helper that returns a violation message or throws a small project-local exception. Keep UsageError creation in GenerateProjects.run, or in a thin Clikt adapter around GenerateProjectRequest.resolve. Preserve the existing messages and behavior for CLI users. Update GenerateProjectsCliTest so command parsing still expects UsageError, while direct resolver/validation tests assert the project-local validation result or exception instead of Clikt.

Notes

DDD/clean architecture lens: keep the application request assembly and feature compatibility policy independent from the Clikt delivery mechanism. This is a small adapter-boundary cleanup, not a redesign.

Fixes #451

Changes

• cli/src/main/kotlin/io/github/cdsap/projectgenerator/cli/GenerateProjectRequest.kt
• cli/src/main/kotlin/io/github/cdsap/projectgenerator/cli/Main.kt
• cli/src/test/kotlin/io/github/cdsap/projectgenerator/cli/GenerateProjectsCliTest.kt

Verification

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