feat(design): integrate agent activity timeline

.project-docs/10-decisions/adr-007-ai-design-living-form-v2.md

@@ -4,6 +4,9 @@
 
 Accepted / implemented
 
+Amended on 2026-09-07 to define operation-scoped public activity as transient
+presentation state beneath the matching optimistic user message.
+
 ## Date
 
 2026-08-30
@@ -27,6 +30,12 @@ versioned Design Specification and a persistent form throughout the design flow.
 - Every mutation carries stable command and semantic operation identities. An
   unknown transport result keeps the same command for replay; revision conflicts
   refresh canonical state without discarding local drafts.
+- While a chat operation is pending, Electron Main may normalize the server's closed
+  `design.assistant.progress` lifecycle into fixed youth-safe stages, and Renderer
+  may show one transient activity panel beneath the matching optimistic user message.
+  Activity is not a canonical Turn, Current Specification state, assistant content,
+  or evidence that a change committed. Model chain-of-thought, prompts, Provider
+  responses, tool arguments, and unvalidated model text are never rendered.
 - Generation is a compile-and-confirm boundary. The server returns an immutable
   Quote for one exact Specification revision; the client displays the public output
   plan, warnings, expiry, and Token Point amount and confirms only the Quote ID.
@@ -51,6 +60,8 @@ and uncertain retries auditable without exposing provider internals.
   old clients and V1 semantic writers receive no compatibility window.
 - Production database cutover, paid Provider activation, and real-account installed
   client smoke remain separate operator gates.
+- Replayed activity and generic terminal Gateway events reconcile by the original
+  operation identity. They do not create another message, form, or retry intent.
 
 ## Supersedes