feat: genesis ceremony task handlers and deterministic task IDs (#41)

## Summary

- **Genesis task handlers**: Implements the four sidecar task handlers
needed for genesis ceremony orchestration:
- `generate-identity` — runs `seid init` to create validator keys and
node identity
- `generate-gentx` — three-step pipeline: `keys add` →
`add-genesis-account` → `gentx`
- `upload-genesis-artifacts` — uploads gentx and identity manifest to S3
per-node
- `assemble-and-upload-genesis` — downloads all node gentxs from S3,
runs `collect-gentxs`, uploads assembled genesis.json
- **Deterministic task IDs**: Engine now accepts caller-provided UUIDs
for idempotent task submission with deduplication. `ErrInvalidTaskID`
sentinel for non-UUID IDs. `TaskMeta` struct embedded in all 16 client
task types for ID propagation.
- **Client ergonomics**: Typed `Submit*Task` convenience methods on
`SidecarClient` for all four new genesis tasks. `CommandRunner`
abstraction for testable `seid` CLI invocations.

## Test plan

- [x] `generate-identity`: seid init args, idempotency via marker,
missing params, seid failure
- [x] `generate-gentx`: full 3-step flow, idempotency, missing params,
keys add failure
- [x] `upload-genesis-artifacts`: gentx + identity upload, idempotency,
missing params, no gentx file
- [x] `assemble-and-upload-genesis`: full flow with S3 mock,
idempotency, missing params, S3 download failure, collect-gentxs failure
- [x] Engine: caller-provided ID, invalid ID validation
(`ErrInvalidTaskID`), dedup active/completed/scheduled
- [x] Server: HTTP-level invalid ID → 400, dedup returns existing ID
- [x] Full test suite passes (`go test ./...`)

Author: bdchatham

serve.go

@@ -45,18 +45,22 @@ var serveCmd = cli.Command{
 		}
 
 		handlers := map[engine.TaskType]engine.TaskHandler{
-			engine.TaskSnapshotRestore:    tasks.NewSnapshotRestorer(homeDir, nil).Handler(),
-			engine.TaskDiscoverPeers:      tasks.NewPeerDiscoverer(homeDir, nil, nil).Handler(),
-			engine.TaskConfigPatch:        tasks.NewConfigPatcher(homeDir).Handler(),
-			engine.TaskConfigApply:        tasks.NewConfigApplier(homeDir).Handler(),
-			engine.TaskConfigValidate:     tasks.NewConfigValidator(homeDir).Handler(),
-			engine.TaskConfigReload:       tasks.NewConfigReloader(homeDir).Handler(),
-			engine.TaskMarkReady:          tasks.MarkReadyHandler(),
-			engine.TaskConfigureGenesis:   tasks.NewGenesisFetcher(homeDir, chainID, nil).Handler(),
-			engine.TaskConfigureStateSync: tasks.NewStateSyncConfigurer(homeDir, nil).Handler(),
-			engine.TaskSnapshotUpload:     tasks.NewSnapshotUploader(homeDir, nil).Handler(),
-			engine.TaskResultExport:       tasks.NewResultExporter(homeDir, nil).Handler(),
-			engine.TaskAwaitCondition:     tasks.NewConditionWaiter(nil).Handler(),
+			engine.TaskSnapshotRestore:          tasks.NewSnapshotRestorer(homeDir, nil).Handler(),
+			engine.TaskDiscoverPeers:            tasks.NewPeerDiscoverer(homeDir, nil, nil).Handler(),
+			engine.TaskConfigPatch:              tasks.NewConfigPatcher(homeDir).Handler(),
+			engine.TaskConfigApply:              tasks.NewConfigApplier(homeDir).Handler(),
+			engine.TaskConfigValidate:           tasks.NewConfigValidator(homeDir).Handler(),
+			engine.TaskConfigReload:             tasks.NewConfigReloader(homeDir).Handler(),
+			engine.TaskMarkReady:                tasks.MarkReadyHandler(),
+			engine.TaskConfigureGenesis:         tasks.NewGenesisFetcher(homeDir, chainID, nil).Handler(),
+			engine.TaskConfigureStateSync:       tasks.NewStateSyncConfigurer(homeDir, nil).Handler(),
+			engine.TaskSnapshotUpload:           tasks.NewSnapshotUploader(homeDir, nil).Handler(),
+			engine.TaskResultExport:             tasks.NewResultExporter(homeDir, nil).Handler(),
+			engine.TaskAwaitCondition:           tasks.NewConditionWaiter(nil).Handler(),
+			engine.TaskGenerateIdentity:         tasks.NewIdentityGenerator(homeDir, nil).Handler(),
+			engine.TaskGenerateGentx:            tasks.NewGentxGenerator(homeDir, nil).Handler(),
+			engine.TaskUploadGenesisArtifacts:   tasks.NewGenesisArtifactUploader(homeDir, nil).Handler(),
+			engine.TaskAssembleAndUploadGenesis: tasks.NewGenesisAssembler(homeDir, nil, nil, nil).Handler(),
 		}
 
 		eng := engine.NewEngine(ctx, handlers)

sidecar/api/openapi.yaml

@@ -132,6 +132,14 @@ components:
       type: object
       required: [type]
       properties:
+        id:
+          type: string
+          format: uuid
+          description: >
+            Caller-provided task identifier. When set, the engine uses this
+            as the canonical ID (enabling deterministic IDs from the controller).
+            If a task with this ID already exists, the request is idempotent
+            and returns the existing ID. When omitted, a random UUID is generated.
         type:
           type: string
           description: Task type identifier.

sidecar/client/client.go

@@ -323,3 +323,31 @@ func (c *SidecarClient) SubmitAwaitConditionTask(ctx context.Context, task Await
 	}
 	return c.SubmitTask(ctx, task.ToTaskRequest())
 }
+
+func (c *SidecarClient) SubmitGenerateIdentityTask(ctx context.Context, task GenerateIdentityTask) (uuid.UUID, error) {
+	if err := task.Validate(); err != nil {
+		return uuid.Nil, fmt.Errorf("task validation failed: %w", err)
+	}
+	return c.SubmitTask(ctx, task.ToTaskRequest())
+}
+
+func (c *SidecarClient) SubmitGenerateGentxTask(ctx context.Context, task GenerateGentxTask) (uuid.UUID, error) {
+	if err := task.Validate(); err != nil {
+		return uuid.Nil, fmt.Errorf("task validation failed: %w", err)
+	}
+	return c.SubmitTask(ctx, task.ToTaskRequest())
+}
+
+func (c *SidecarClient) SubmitUploadGenesisArtifactsTask(ctx context.Context, task UploadGenesisArtifactsTask) (uuid.UUID, error) {
+	if err := task.Validate(); err != nil {
+		return uuid.Nil, fmt.Errorf("task validation failed: %w", err)
+	}
+	return c.SubmitTask(ctx, task.ToTaskRequest())
+}
+
+func (c *SidecarClient) SubmitAssembleAndUploadGenesisTask(ctx context.Context, task AssembleAndUploadGenesisTask) (uuid.UUID, error) {
+	if err := task.Validate(); err != nil {
+		return uuid.Nil, fmt.Errorf("task validation failed: %w", err)
+	}
+	return c.SubmitTask(ctx, task.ToTaskRequest())
+}