feat(sandokan-core): B1.1 — contrato del orquestador

Primer crate de la Fase B. Define SOLO el contrato del orquestador
sandokan (library horizontal embebible, no daemon supremo):

- Intent / ExecContext / IsolationLevel — qué orquestar
- ExecHandle — referencia a una entidad encarnada
- LifecycleEvent / TelemetryFrame — observabilidad (wire types)
- EngineError — taxonomía de fallas
- trait Engine — run/stop/list/status/telemetry (poll-based, sin
  streams sobre trait objects, para que las 3 impls lo cumplan
  uniformemente)

Las impls concretas (LocalEngine, DaemonEngine, RemoteEngine) vendrán
en crates separados (sandokan-local, sandokan-daemon, sandokan-remote).

3 tests verdes. cargo check --workspace verde.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Cargo.lock

@@ -10127,6 +10127,18 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "sandokan-core"
+version = "0.1.0"
+dependencies = [
+ "async-trait",
+ "brahman-card",
+ "sandokan-lifecycle",
+ "serde",
+ "thiserror 2.0.18",
+ "ulid",
+]
+
 [[package]]
 name = "sandokan-lifecycle"
 version = "0.1.0"