feat(flows): create flow with content and publish in one call

[realcodesiman]

Summary

• POST /v1/flows (flows.create) now accepts an optional spec (flow-spec DSL) or raw nodes/edges graph to seed the draft's content in the same call, instead of requiring a separate flows.updateDraft/flows.publish round trip.
• Adds publish: true to validate the supplied graph exactly like flows.publish and create the flow's first immutable version in the same call.
• For the raw graph shape, node position/measured, node ids, and edge id/handles are all optional/caller-arbitrary — generated or remapped server-side, so only the flow's actual content needs to be sent.

Changes

• packages/flow-config/src/authoring/normalize-graph.ts (new): normalizeAuthoredGraph lays out positionless nodes with the existing BFS layoutNodes, remaps every caller-authored node id to an internal createId() id (persisted node ids must be numeric per baseNodeSchema/zodBigintAsString, so an arbitrary caller id like "n1" would otherwise fail publishFlowSchema), and rewrites edge ids/handles to match.
• apps/builder/src/features/flows/lib/resolve-flow-graph-input.ts (new): resolves flows.create's { spec } or { nodes, edges } content into the graph flowService.createDraft persists, running publishFlowSchema validation only when publish: true is requested.
• packages/business/src/flow/service.ts: flowService.createDraft accepts an optional pre-resolved graph, falling back to today's single default "Send Message" start node when omitted.
• apps/builder/src/features/flows/schema/action.ts: new createFlowRequest schema (.extend() + .superRefine()) rejecting spec combined with nodes/edges, edges without nodes, and publish: true without content.
• apps/builder/src/features/flows/api/public.ts: wires flows.create to resolve content, create the draft, and optionally publish; flows.validate handler updated for the new compileAndValidateSpec return shape.
• Docs updated: docs/flows.md, apps/builder/src/features/capabilities/api/public.ts descriptions, apps/mcp-server/SKILL.md.

Test plan

• pnpm lint
• pnpm --filter @chatbotx.io/flow-config check-types
• pnpm --filter @chatbotx.io/business check-types
• pnpm --filter builder check-types
• pnpm --filter @chatbotx.io/flow-config test (555/555)
• pnpm --filter @chatbotx.io/business test (2631/2631)
• pnpm --filter builder test (3997/3997, 2 pre-existing skips)
• Throwaway script verifying normalizeAuthoredGraph end-to-end (positions, id remap, edge handles, startNodeId)
• Manual verification against a running dev stack (Postgres/Redis/seeded workspace/API token) — not performed; substituted the throwaway script above per project convention