chore: migrate Gradle build files from Groovy DSL to Kotlin DSL

[Elforama]

Summary

Migrates all 3 Gradle build files from Groovy DSL (.gradle) to Kotlin DSL (.gradle.kts), following the official Android migration guide.

Changes

gradle/libs.versions.toml

• Added roborazzi plugin entry to [plugins] section (was previously only available as a classpath library dependency)

settings.gradle → settings.gradle.kts

• Added pluginManagement block with repositories (absorbs what was in root buildscript { repositories {} })
• Added dependencyResolutionManagement block with FAIL_ON_PROJECT_REPOS mode (centralizes repositories that were scattered across root allprojects {} and app/build.gradle)
• Converted include and rootProject.name to Kotlin syntax

build.gradle → build.gradle.kts (root)

• Replaced buildscript { classpath ... } block with plugins { alias(libs.plugins.xxx) apply false } using version catalog aliases
• Converted allprojects {} block: apply plugin: → apply(plugin = ...), ktlint {} → configure<KtlintExtension> {}
• Removed allprojects { repositories {} } (moved to settings.gradle.kts)
• Converted ext {} properties to ext { set("key", "value") } syntax
• Converted subprojects {} block: detekt {} → configure<DetektExtension> {}, spotless {} → configure<SpotlessExtension> {}
• Converted clean task to tasks.register<Delete>("clean") with non-deprecated layout.buildDirectory

app/build.gradle → app/build.gradle.kts

• Plugins: Converted all plugin declarations to version catalog aliases; moved apply plugin: 'com.google.gms.google-services' from bottom of file into plugins {} block
• loadExtraProperties function: Rewritten in Kotlin with Properties/FileInputStream imports, stringPropertyNames() iteration (avoids Kotlin val keyword conflict), and a file-exists guard for the gitignored treetracker.keys.properties
• Android block: Added = assignment operators to all property setters, .toInteger() → .toInt()
• Build types: debug/release use getByName(), custom types (prerelease, beta, dev) use create(). Reordered so debug is configured before types that reference it via initWith(getByName("debug")). Boolean property renames: minifyEnabled → isMinifyEnabled, debuggable → isDebuggable, coreLibraryDesugaringEnabled → isCoreLibraryDesugaringEnabled
• signingConfig: signingConfigs.debug → signingConfigs.getByName("debug")
• packagingOptions: Replaced deprecated API with packaging { resources { excludes += setOf(...) } }
• testOptions: includeAndroidResources → isIncludeAndroidResources, .toLowerCase() → .lowercase()
• Roborazzi task config: def → val, tasks.withType(Test) → tasks.withType<Test>(), .matches("regex") → .matches(Regex("regex")), $buildDir → layout.buildDirectory.get().asFile
• Dependencies: Added parentheses to all declaration calls
• Removed standalone repositories {} block (now handled by settings)
• Fixed missing inner quotes on API_GATEWAY buildConfigField in defaultConfig

Test plan

• ./gradlew projects — settings parse correctly
• ./gradlew assembleDebug — debug build succeeds
• ./gradlew testDebugUnitTest — unit tests pass
• Verify assembleRelease, assembleBeta, assemblePrerelease, assembleDev build types
• Verify ktlintCheck, detekt, spotlessCheck code quality plugins still work
• Verify Android Studio sync works correctly

[github-actions]

👋 Hi @Elforama, thanks for the contribution!

Before this PR can be reviewed and merged, please add:

• a 🎥 screen recording / video demonstrating the change — a video is required even when there are no UI changes, to show that the parts of the app affected by this change still work
• a 🖼️ screenshot of the UI change (or mark the PR as non-ui if there is no UI change)

Just drag-and-drop the file(s) into the PR description and GitHub will upload them. This check re-runs automatically when you edit the description.

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