This commit provides a comprehensive update to the project's technical documentation, capturing the successful completion of the "Android-first" Kotlin Multiplatform (KMP) structural migration. It establishes a new single source of truth for migration status, architectural decisions, and build-logic conventions.

Key documentation changes include:

- **Migration Status & Roadmap:**
  - Created `docs/kmp-status.md` and `docs/roadmap.md` to track the 98% completed structural migration and outline future priorities (iOS, serial transport, MapLibre).
  - Archived legacy migration notes into `docs/archive/` to maintain a clean record of completed phases.
  - Formally documented the "Nordic Hybrid" BLE abstraction and the transition to Koin 4.x as completed architectural pillars.

- **Architecture & Decisions:**
  - Introduced `docs/decisions/` to house active ADRs (Architecture Decision Records).
  - Added `navigation3-parity-2026-03.md` defining the shared route model and parity testing strategy between Android and Desktop.
  - Documented the global disabling of Koin A1 compile-safety to support Clean Architecture dependency inversion across modules.
  - Established `core:testing` as the centralized repository for shared test fakes and fixtures.

- **Build Logic & Optimization:**
  - Created a comprehensive `docs/BUILD_LOGIC_INDEX.md` and developer guides for convention plugins.
  - Centralized `kotlin("test")` dependencies in `KmpLibraryConventionPlugin` to eliminate boilerplate across feature modules.
  - Standardized the `jvmAndroidMain` hierarchy via the new `meshtastic.kmp.jvm.android` plugin, removing manual source-set wiring and hierarchy warnings.

- **Maintenance & Guidelines:**
  - Updated `AGENTS.md` and playbooks to reflect the shift toward shared ViewModels in `commonMain` and the elimination of 11 redundant Android ViewModel wrappers.
  - Updated Koin configuration and verification tests to align with Koin 0.4.0 compiler plugin requirements.

Specific changes:
- Created 10+ new documentation files and archived 8 legacy files.
- Refined `KoinConventionPlugin` to configure `koinCompiler` settings.
- Migrated 4 core modules and 7 feature modules to use optimized build conventions.
- Synchronized `AGENTS.md` with 2026 KMP industry standards for DI and testing.

Signed-off-by: James Rich <[email protected]>