fix: resolve all compilation errors in Rust/Tauri backend

[superninja-app]

Summary

This PR fixes all compilation errors in the V-Streaming Rust/Tauri backend, bringing the project from hundreds of errors down to a clean compile.

Changes Made

Missing Serialize/Deserialize Derives

• Added Serialize/Deserialize derives to types in: composition.rs, vtuber.rs, ui.rs, onboarding.rs, plugin.rs, gpu.rs, capture.rs, audio.rs, and others

Missing Engine Methods

• CompositionEngine: Added 10 missing methods (layer transforms, crops, filters, etc.)
• TipEcosystemEngine: Added update_goal, update_reward
• SponsorMarketplaceEngine: Added get_sponsorship
• TelemetryEngine: Added get_error_reports, get_recent_error_reports, acknowledge_error
• PerformanceEngine: Added delete_profile

Type Mismatches & Return Types

• Wrapped return values in Ok() where functions expected Result<T, String> but methods returned T directly
• Added .map(|_| ()) for functions returning Result<(), String> when engine methods return Result<T, String>
• Removed invalid .cloned() calls on Option<T> types
• Fixed Option<f32> vs f32 type mismatch in profiler.rs

Async/Lifetime Fixes

• Added explicit lifetime '_ to tauri::State<'_, AppState> in async analytics functions
• Fixed MutexGuard held across .await points (not Send-safe)

Struct & Import Fixes

• Added can_undo/can_redo fields to UndoRedoInfo
• Added acknowledged field to ErrorReport
• Fixed fmt import conflict in logging.rs
• Fixed plugin_metadata macro import in cli.rs
• Added From<PluginError> impl for CliError
• Fixed String vs &str issues in cli.rs

Engine Initialization

• Added .expect() to VtuberEngine::new(), UiEngine::new(), OnboardingEngine::new() which return Result
• Added Default derive to RealTimeAnalytics

Restructured apply_for_sponsorship

• Constructs SponsorshipApplication struct with all required fields

Result

• ✅ cargo check passes successfully
• ⚠️ Only warnings remain (unused imports/variables) - can be addressed in a follow-up

Files Changed (23 files)

All changes are in src-tauri/src/