feat(a2ui)!: migrate to A2UI v0.9.1 stable wire format

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Summary

Migrates every A2UI touchpoint from the legacy wire shape (beginRendering/surfaceUpdate/dataModelUpdate, type-keyed component wrappers, literalString wrappers, children.explicitList) — now classified upstream as the deprecated v0.8-legacy lineage — to the A2UI v0.9.1 stable release. Clean cutover, no legacy acceptance. Phase 1 of 4; design in docs/superpowers/specs/2026-08-17-a2ui-v09-stable-migration-design.md, plan in docs/superpowers/plans/2026-08-17-a2ui-v09-phase1-cutover.md.

• @threadplane/a2ui: v0.9 envelopes (createSurface/updateComponents/updateDataModel/deleteSurface, each with version: "v0.9"), flat components, bare-literal + {path} + typed {call} dynamic values, event/functionCall actions, checks types, client→agent action/error/capabilities messages, A2UI_MIME_TYPE/A2UI_BASIC_CATALOG_ID constants. Parser skips unknown envelope keys (v1.0 forward-compat). deleteByPointer implements the v0.9 array-delete rule. Types verified against the official machine-readable schemas (server_to_client.json, basic-catalog.json, common_types.json).
• @threadplane/chat: surface store re-gated on createSurface + root component (progressive rendering per spec) with incremental component merge and path/value/delete data-model semantics; surface-to-spec consumes flat components; partial-args bridge synthesizes a missing createSurface (replacing beginRendering synthesis); all 18 catalog components re-propped to spec enums; MultipleChoice → ChoicePicker (variant/displayStyle/filterable); action messages are v0.9-shaped with plain-object context; theme flows from createSurface.theme.
• Python emitters: both example apps' schema prompt (a2ui_v09.py), envelope tool/normalizer, and graph ordering (createSurface-first + synthesis); cockpit aviation graphs' structured-output specs + prompts; deployments/ag-ui-dev copy byte-identical.
• Fixtures/docs: all 6 e2e fixtures regenerated (cockpit ones round-trip-validated against the new pydantic models); 13+ website MDX pages, READMEs, cockpit prompt docs, api-docs regenerated.

Follow-up phases (separate PRs): client-side functions, validation checks, sendDataModel round-trip.

Verification

• libs/a2ui 59 unit tests; libs/chat 1126 unit tests; both libs build + lint clean; native-ESM import check of the built a2ui dist passes
• Python: examples/chat 56 passed, examples/ag-ui 23 passed; cockpit graphs 10-part envelope smoke passed in both venvs
• E2E (aimock): examples-chat a2ui + contact-form ✅, examples-ag-ui twins ✅, cockpit-chat-a2ui ✅, cockpit-ag-ui-a2ui ✅
• Prod builds: examples-chat, examples-ag-ui, website ✅
• nx affected -t lint test build: green except two pre-existing worktree-environment failures in untouched projects (cockpit-telemetry:lint posthog-js specifier vs local install; cockpit:build Turbopack workspace-root inference) — zero diff vs main in both projects
• Live Chrome smoke (real gpt-5-mini, langgraph dev): prompted the canonical demo's A2UI mode; the sub-LLM emitted v0.9 envelopes, the contact-form surface rendered progressively, and clicking Send produced the spec client action on the wire: {"version":"v0.9","action":{"name":"send_contact_form","surfaceId":"contact-form-surface","sourceComponentId":"sendButton","timestamp":"…","context":{…},"label":"Send"}} (verified via thread state), with the agent responding to it.

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Project	Deployment	Actions	Updated (UTC)
threadplane	Ready	Preview	Aug 17, 2026 4:24pm