feat: command.execute returns the lifecycle pairing id ({matched, commandId?})

CommandService.execute now returns a CommandExecution — the normalized
result plus the commandId minted for its command/run/command/done records —
and the wire admission value carries commandId exactly when matched, so the
issuing client can correlate its RPC acknowledgment with the flow node the
lifecycle events produce. apiproxy api/schema/handler, the connection
fixture, and the TUI/plan/goal consumers follow the new shape.

packages/host/apiproxy/src/api-proxy.ts

@@ -921,9 +921,13 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
         try {
           // Pure admission: the executor's durable command/run + command/done
           // pair (broadcast on the mux stream) carries the outcome; the
-          // response only reports whether the line resolved to a handler.
-          const result = await commands.execute(found.agent, line, signal)
-          return ok(request, { matched: result !== undefined })
+          // response reports whether the line resolved to a handler, plus the
+          // minted pairing id so the issuing client can correlate its request
+          // with the flow node the lifecycle events produce.
+          const execution = await commands.execute(found.agent, line, signal)
+          return ok(request, execution === undefined
+            ? { matched: false }
+            : { matched: true, commandId: execution.commandId })
         } catch (error: unknown) {
           if (signal.aborted) return err(request, { code: 'cancelled', message: 'command execution was aborted', details: {} })
           return err(request, { code: 'internal', message: `command failed: ${String(error)}`, details: {} })

packages/host/apiproxy/src/api/commands.schema.ts

@@ -32,7 +32,8 @@ export const commandExecuteRequestSchema = z.object({
   line: z.string(),
 }) satisfies z.ZodType<Wire<RequestPayload<'command.execute'>>>
 
-/** command.execute response value: pure admission — outcomes ride the logged lifecycle events, never this response. */
+/** command.execute response value: pure admission — outcomes ride the logged lifecycle events; commandId (present exactly when matched) correlates with them. */
 export const commandExecuteValueSchema = z.object({
   matched: z.boolean(),
+  commandId: z.string().min(1).optional(),
 }) satisfies z.ZodType<Wire<ResponseValue<'command.execute'>>>

packages/host/apiproxy/src/api/commands.ts

@@ -36,10 +36,12 @@ export interface CommandsApi {
    * when syntax or name does not resolve (the client falls back to its
    * default sink). The handler's outcome does NOT ride the response: the host
    * executor durably logs the lifecycle (`command/run`/`command/done`), which
-   * broadcasts on the mux stream and renders as a persistent flow node. The
-   * signal rides beside the request, never on the wire: the fetch carrier's
-   * request signal cancels the running handler.
+   * broadcasts on the mux stream and renders as a persistent flow node.
+   * `commandId` is present exactly when matched — the minted lifecycle
+   * pairing id, letting the issuing client correlate this acknowledgment
+   * with that flow node. The signal rides beside the request, never on the
+   * wire: the fetch carrier's request signal cancels the running handler.
    */
   execute(request: RpcRequest<{ sessionId: SessionId; line: string }>, signal: AbortSignal):
-  Promise<RpcResponse<{ matched: boolean }>>
+  Promise<RpcResponse<{ matched: boolean; commandId?: string }>>
 }