decompose architecture into 38 atomic tasks across 12 parallel generations

Decompose the reviewed architecture specs into taskgraph-managed tasks:
- 2 setup tasks (project init, test infrastructure)
- 4 schema tasks (enums, node attrs, edge attrs, graph schemas)
- 1 error hierarchy task
- 6 graph tasks (FlowGraph class, 3 construction paths, queries, validation)
- 5 analysis tasks (type-compat, build-type-edges, ordering, template-validation, defaults)
- 5 component tasks (Operation, Sequential, Parallel, Conditional, Map)
- 2 host config tasks (GraphologyHostConfig, ReactiveHostConfig)
- 4 reactive tasks (WorkflowRoot, node-status, max-concurrency, retry-semantics)
- 3 review tasks (foundation, reactive-and-hosts, complete-library)
- 5 meta cluster tasks (schema, graph, component, reactive, analysis layers)
- 1 API exports task

Validated with taskgraph: zero cycles, 38 tasks, 12 parallel generations.
Critical path: 12 tasks through reactive execution layer.

tasks/schema-graph-schemas.md

@@ -0,0 +1,39 @@
+---
+id: schema/graph-schemas
+name: Define SerializedGraph factory and OperationGraphSerialized/CallGraphSerialized schemas
+status: pending
+depends_on:
+  - schema/node-attrs
+  - schema/edge-attrs
+scope: narrow
+risk: low
+impact: component
+level: implementation
+---
+
+## Description
+
+Define the generic `SerializedGraph` factory function that produces graphology native JSON format schemas, and the two specialized serialization types for operation graphs and call graphs.
+
+## Acceptance Criteria
+
+- [ ] `src/schema/graph.ts` exports `SerializedGraph` factory function
+- [ ] `SerializedGraph<N, E, G>`: generic factory producing `Type.Object` with `attributes` (GraphAttrs), `options` ({type: "directed", multi: false, allowSelfLoops: false}), `nodes` (Array of {key, attributes}), `edges` (Array of {key, source, target, attributes})
+- [ ] `OperationGraphSerialized`: `SerializedGraph(OperationNodeAttrs, OperationEdgeAttrs, Type.Object({}))` — no graph-level attributes
+- [ ] `CallGraphSerialized`: `SerializedGraph(CallNodeAttrs, CallEdgeAttrs, Type.Object({}))` — no graph-level attributes
+- [ ] `FlowGraphSerialized` type alias for the general case (used by `fromJSON`)
+- [ ] Edge key convention documented: `${source}->${target}` for simple cases, `${source}->${target}:${edgeType}` for call graph depends_on edges
+- [ ] `src/schema/index.ts` re-exports graph schemas
+- [ ] Unit tests: `Value.Check()` against valid and invalid serialized graph data
+
+## References
+
+- docs/architecture/schema.md — SerializedGraph factory, FlowGraphSerialized variants, edge key convention
+
+## Notes
+
+> To be filled by implementation agent
+
+## Summary
+
+> To be filled on completion