docs(automation): correct run-history durability + region-step nesting in flows.mdx

The "Runs" section still described run history as an in-memory ring buffer whose
`sys_automation_run` rows "hold only live pauses", so "history starts fresh on
each boot". That predates the durable terminal run history (#2585): terminal
runs (completed / failed) are mirrored to `sys_automation_run` with a bounded
step log, and `listRuns` / `getRun` merge it so a run's status / steps / failure
reason survive a restart or ring-buffer eviction. Also note the Studio Runs
panel now nests body steps by iteration / branch / handler (#1505, objectui
#2667). Surfaced by the docs-drift check on #3240.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VuvxWgoadqryqBcjs7TpVi

Author: claude

content/docs/automation/flows.mdx

@@ -445,10 +445,12 @@ GET /api/v1/automation/{flow}/runs/{runId}/screen  # re-fetch a paused screen
 ```
 
 Each run's `steps[]` records every executed node — including loop iterations,
-parallel branch bodies, and try/catch region steps — and the Studio flow
-designer surfaces the same data in its **Runs** side panel. Run history is an
-in-memory ring buffer (the durable rows in `sys_automation_run` hold only
-*live pauses*), so history starts fresh on each boot.
+parallel branch bodies, and try/catch region steps — which the Studio flow
+designer surfaces, nested by iteration / branch / handler, in its **Runs** side
+panel. Recent runs are held in an in-memory ring buffer; terminal runs
+(completed / failed) are also mirrored to `sys_automation_run` as durable
+history with a bounded step log, so `listRuns` / `getRun` still report a run's
+status, steps, and failure reason after a restart or ring-buffer eviction.
 
 ## Edges