Add Flutter mobile app and monorepo packaging

[0xfnzero]

Summary

• Reorganizes the repository into the new monorepo layout with crates/, apps/desktop/, apps/mobile/, packages/, and docs/.
• Adds the Flutter iOS/Android mobile app scaffold with flutter_rust_bridge integration, generated bindings, wallet storage, dApp WebView/provider flow, signing confirmation, biometric gate, Squads screen, and native Android/iOS bridge build scripts.
• Moves the existing desktop app into apps/desktop, keeps Program deploy/upgrade/source-build workflows desktop-only, and adds shared Rust app services plus mobile bridge crates.
• Adds unified package targets that copy artifacts into root release/: make package-android, make package-ios, make package-macos, make package-windows, and make package.
• Updates English and Chinese README files with a Word-style outline, platform matrix, development setup, run commands, packaging instructions, and pre-submit validation steps.

Validation

• git diff --cached --check
• make -n package
• cargo fmt --all -- --check
• cargo check --workspace --all-features
• cargo clippy --workspace --all-targets --all-features -- -D warnings
• cargo test --workspace
• flutter analyze
• flutter test --dart-define=FNZERO_MOBILE_DEV_BRIDGE=true
• make package-android
• make package-macos

Package outputs verified locally

• Android APK/AAB copied to release/android/
• macOS .app/.dmg copied to release/macos/

Known follow-ups

• iOS package/archive is blocked on this machine until the matching Xcode iOS platform/runtime is installed. Local xcodebuild reported iOS 26.5 is not installed / no installed simulator runtimes.
• Windows packaging should run on a Windows/MSVC build host.
• Mobile Pump submit/runtime smoke tests still need funded devnet wallets and device/emulator validation.