refactor: created multiple modules

[kikoso]

PR Description

Goal

The goal of this PR is to centralize the build configuration and migrate the standalone sample projects into a unified multi-module Gradle structure. This significantly reduces boilerplate, simplifies dependency management, and improves the overall maintainability of the android-samples repository.

Proposed Changes

Architecture & Build System

• Multi-Module Consolidation: Migrated multiple standalone projects (ApiDemos, FireMarkers, WearOS, and several tutorials) into a single root Gradle project.
• Centralized Settings: Introduced a root settings.gradle.kts to manage all subprojects from a single point.
• Unified Dependency Management: Implemented a root gradle/libs.versions.toml version catalog, replacing individual catalog files in subdirectories.
• Plugin Management: Centralized plugin declarations in the root project, referencing them via the version catalog.

Cleanup & Optimization

• Boilerplate Reduction: Removed over 4,000 lines of redundant Gradle configuration files, including duplicated gradlew wrappers, settings.gradle.kts files, and local libs.versions.toml files.
• Consistency: Standardized SDK versions and dependency versions across all modules.

Verification Plan

Since this is a build-system refactor, verification focuses on project compilation and structure.

Automated Tests

• Run ./gradlew assembleDebug from the root to ensure all modules build correctly.
• Run ./gradlew lint to verify that linting still works across the multi-module structure.

Manual Verification

• Inspect the file system to ensure all redundant gradle directories and wrappers have been removed as intended.
• Verify that individual apps (e.g., ApiDemos, FireMarkers) can still be launched and function correctly after the migration.

[github-advanced-security]

Android Lint found more than 20 potential problems in the proposed changes. Check the Files changed tab for more details.

[snippet-bot]

Here is the summary of changes.

You are about to add 2 region tags.

• settings.gradle.kts:17, tag maps_android_settings_plugin_management
• settings.gradle.kts:27, tag maps_android_settings_dependency_resolution_management

You are about to delete 2 region tags.

• snippets/settings.gradle.kts:17, tag maps_android_settings_plugin_management
• snippets/settings.gradle.kts:27, tag maps_android_settings_dependency_resolution_management

---

This comment is generated by snippet-bot.
If you find problems with this result, please file an issue at:
https://github.com/googleapis/repo-automation-bots/issues.
To update this comment, add snippet-bot:force-run label or use the checkbox below:

• Refresh this comment