0.3.0

Catch-up release. Brings the Unity SDK in line with chain changes
that landed during the 2026-04-17 → 2026-05-03 stretch.

Wire-format compatibility:
- StringTolerantUlongConverter + nullable variant; VelocityJson
  shared serializer settings. Every DTO now accepts the chain's
  stringified u64 wire format (heights, balances, fuel, fees,
  rates, lifetime counters).

Bridge settlement endpoints:
- BridgeOutStatus DTO + GetBridgeOutStatusAsync /
  WaitForBridgeOutAsync — closes the forward-leg loop without the
  SDK touching a destination-chain RPC.
- BridgeInStatus DTO + GetBridgeInStatusAsync — Hive/Solana →
  Velocity deposit progress.
- HiveBridgeMemo helper for the velocity:<chain>:<address> memo
  format Hive depositors paste.

Plus the post-0.2.0 polish that merged on main:
- Error-body parsing, configurable Timeout.
- Auto-reconnect streaming, Task/IAsyncEnumerable -> coroutine
  adapters.
- GetMetricsAsync, GetValidatorAttestationHealthAsync.
- WebGL SSE via .jslib EventSource shim.
- Dormant unityci/editor CI job.

Still deferred: player-signed actions, Phase 4-6 (AMM / flash
loans / capability payment) action bodies, Solana-side mint_from_proof,
sample .unity scene + editor windows. Demo-targeted catch-up.