refactor: code smell fixes — tests, events, naming

- Tests for ExecutePipelineHandler (happy path, fallback, disabled skip, failure retry, not found)
- Tests for ProcessNextJobHandler (empty queue, process, drain multiple)
- DerivativeGenerated domain event + event-payload mapping + event_store aggregate
- Renamed event-payload → adapters-event-payload, event-transport → adapters-event-transport

Cargo.lock

@@ -17,6 +17,30 @@ dependencies = [
  "uuid",
 ]
 
+[[package]]
+name = "adapters-event-payload"
+version = "0.1.0"
+dependencies = [
+ "chrono",
+ "domain",
+ "serde",
+ "serde_json",
+ "uuid",
+]
+
+[[package]]
+name = "adapters-event-transport"
+version = "0.1.0"
+dependencies = [
+ "adapters-event-payload",
+ "async-trait",
+ "domain",
+ "futures",
+ "serde_json",
+ "tokio",
+ "tracing",
+]
+
 [[package]]
 name = "adapters-exif"
 version = "0.1.0"
@@ -30,10 +54,10 @@ dependencies = [
 name = "adapters-nats"
 version = "0.1.0"
 dependencies = [
+ "adapters-event-transport",
  "async-nats",
  "async-trait",
  "domain",
- "event-transport",
  "futures",
  "tokio",
  "tracing",
@@ -43,11 +67,11 @@ dependencies = [
 name = "adapters-postgres"
 version = "0.1.0"
 dependencies = [
+ "adapters-event-payload",
  "anyhow",
  "async-trait",
  "chrono",
  "domain",
- "event-payload",
  "serde",
  "serde_json",
  "sqlx",
@@ -451,6 +475,7 @@ name = "bootstrap"
 version = "0.1.0"
 dependencies = [
  "adapters-auth",
+ "adapters-event-transport",
  "adapters-nats",
  "adapters-postgres",
  "adapters-storage",
@@ -461,7 +486,6 @@ dependencies = [
  "axum",
  "domain",
  "dotenvy",
- "event-transport",
  "presentation",
  "tokio",
  "tower-http",
@@ -880,30 +904,6 @@ dependencies = [
  "pin-project-lite",
 ]
 
-[[package]]
-name = "event-payload"
-version = "0.1.0"
-dependencies = [
- "chrono",
- "domain",
- "serde",
- "serde_json",
- "uuid",
-]
-
-[[package]]
-name = "event-transport"
-version = "0.1.0"
-dependencies = [
- "async-trait",
- "domain",
- "event-payload",
- "futures",
- "serde_json",
- "tokio",
- "tracing",
-]
-
 [[package]]
 name = "exr"
 version = "1.74.0"
@@ -4262,6 +4262,7 @@ dependencies = [
 name = "worker"
 version = "0.1.0"
 dependencies = [
+ "adapters-event-transport",
  "adapters-exif",
  "adapters-nats",
  "adapters-postgres",
@@ -4273,7 +4274,6 @@ dependencies = [
  "async-trait",
  "domain",
  "dotenvy",
- "event-transport",
  "futures",
  "tokio",
  "tracing",