What feature or improvement would you like to see?

Proposed Architecture

The codebase will be reorganized to isolate the native platforms and the Godot editor project into a clean workspace:

godot-admob-plugin/
├── .github/workflows/   # Consolidated CI/CD for all platforms
├── scripts/             # Global build and export scripts
├── platforms/           # Unified source code directory
│   ├── android/         # Native Android Plugin (Gradle/Kotlin/Java)
│   ├── ios/             # Native iOS Plugin (Xcode/Objective-C++/SCons)
│   └── godot_editor/    # The GDScript Editor Plugin (Godot Project environment)

Release Distribution (Multi-Version Matrix)

Because Godot's GDExtension ABI (iOS) and Android Plugin API can change between minor/patch versions, it is not safe to distribute a single binary compiled against the latest version to all users.
Therefore, the CI will continue to build native binaries for multiple Godot versions.
The difference is that now, instead of creating releases across three different repositories, the CI will upload all platform/version ZIP combinations (e.g., poing-godot-admob-android-v4.3.0.zip, poing-godot-admob-ios-v4.6.1.zip) as assets to a single GitHub Release on the monorepo. This is a very safe and standard practice.

Goals & Benefits

• Single Source of Truth: One PR can now contain GDScript, Kotlin/Java, and Objective-C++ changes simultaneously.
• Lower Barrier to Entry: Contributors only need to fork one repository instead of three.
• Unified CI/CD: One GitHub Actions pipeline to run builds for all platforms.
• Simplified Releases: All generated native binaries will be centralized in the main plugin's releases page.

Tasks

• Migrate the Android and iOS source code into platforms/android and platforms/ios. (Note: Using git subtree add is recommended here so we keep the old commit history from the archived repos).
• Move the existing GDScript plugin and project.godot into the new platforms/godot_editor/ directory.
• Consolidate GitHub Actions workflows into the main .github/workflows/ directory. The matrix build generating multiple ZIPs per Godot version will remain intact but all ZIPs will be uploaded to the same release tag.
• Update BASE_URL in android_handler.gd and ios_handler.gd to point to the new monorepo's release page instead of the deprecated repos.
• Disable the automatic update checking system in the GDScript plugin, as a new architecture for auto-updating needs to be designed. (Note: The initial automatic download of the missing binaries must still function normally).
• Update documentation (README.md, etc.) to point to the new monorepo workflow.
• Archive godot-admob-android, godot-admob-ios, and godot-admob-versions repositories (mark as read-only).

Is your feature request related to a problem? If so, please describe.

Currently, the Godot AdMob Plugin relies on Git submodules to manage the native Android and iOS implementations (godot-admob-android and godot-admob-ios). This architecture creates significant friction for contributors, who must fork and manage three separate repositories to make a single feature change. It also complicates version management and CI/CD pipelines.

To improve the developer experience and simplify maintenance, we need to migrate the existing submodules into a single monorepo.

Additional context

No response