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

crates/adapters/event-payload/Cargo.toml

@@ -1,5 +1,5 @@
 [package]
-name = "event-payload"
+name = "adapters-event-payload"
 version = "0.1.0"
 edition = "2024"
 

crates/adapters/event-payload/src/lib.rs

@@ -34,6 +34,12 @@ pub enum EventPayload {
         asset_id: String,
         timestamp: String,
     },
+    DerivativeGenerated {
+        asset_id: String,
+        derivative_id: String,
+        profile: String,
+        timestamp: String,
+    },
     JobEnqueued {
         job_id: String,
         job_type: String,
@@ -59,6 +65,7 @@ impl EventPayload {
             Self::ShareCreated { .. } => "shares.created",
             Self::ShareRevoked { .. } => "shares.revoked",
             Self::SidecarSyncRequested { .. } => "sidecars.sync_requested",
+            Self::DerivativeGenerated { .. } => "derivatives.generated",
             Self::JobEnqueued { .. } => "jobs.enqueued",
             Self::JobCompleted { .. } => "jobs.completed",
             Self::JobFailed { .. } => "jobs.failed",
@@ -123,6 +130,17 @@ impl From<&DomainEvent> for EventPayload {
                 asset_id: asset_id.to_string(),
                 timestamp: timestamp.to_string(),
             },
+            DomainEvent::DerivativeGenerated {
+                asset_id,
+                derivative_id,
+                profile,
+                timestamp,
+            } => Self::DerivativeGenerated {
+                asset_id: asset_id.to_string(),
+                derivative_id: derivative_id.to_string(),
+                profile: profile.clone(),
+                timestamp: timestamp.to_string(),
+            },
             DomainEvent::JobEnqueued {
                 job_id,
                 job_type,
@@ -222,6 +240,17 @@ impl TryFrom<EventPayload> for DomainEvent {
                 asset_id: SystemId::from_uuid(parse_uuid(&asset_id, "asset_id")?),
                 timestamp: parse_timestamp(&timestamp)?,
             },
+            EventPayload::DerivativeGenerated {
+                asset_id,
+                derivative_id,
+                profile,
+                timestamp,
+            } => DomainEvent::DerivativeGenerated {
+                asset_id: SystemId::from_uuid(parse_uuid(&asset_id, "asset_id")?),
+                derivative_id: SystemId::from_uuid(parse_uuid(&derivative_id, "derivative_id")?),
+                profile,
+                timestamp: parse_timestamp(&timestamp)?,
+            },
             EventPayload::JobEnqueued {
                 job_id,
                 job_type,