fix(central-ui): Flow Debugger spawn edges — real arrowhead + bolt badge; spawner picked by trigger attribute

The trigger-cascade (Spawn) edge used a lightning-bolt marker IN PLACE of the arrowhead. On the upward
Tags→Site hop the bolt sat on top of the riser and read as a broken arrow (rig screenshot 2026-09-08).
Every connector now ends in an ordinary arrowhead; the bolt is a badge (circle + bolt) centred on the
connector's vertical run (FlowGraphView.SpawnBadgePoint, kept in step with OrthogonalPath/AsyncPath).

Same screenshot, second defect: the cascade spawned by "RecipeDownloadFlag = false" was drawn from the
LAST write of the burst (RecipeProcessedFlag) because all four writes share a millisecond and the
spawner rule was time-only. FlowGraphBuilder now prefers the parent's last AttributeWrite of the attribute
the child's triggerAttribute names (at or before the child, else the last such write); the time/position
rules remain the fallback when the child names no attribute or the parent never wrote it.

Verified live on the rebuilt rig (DelmiaSim01 / DelmiaReceiverSimulator): both spawn edges show an
arrowhead + badge, the second one originates from the RecipeDownloadFlag write. bUnit + builder tests
updated/added; Playwright FlowDebuggerTests 4/4.

Claude-Session: https://claude.ai/code/session_01NcMG6xXdsJbmD2wYAgkK29

docs/requirements/Component-CentralUI.md

@@ -218,7 +218,7 @@ Per-leaf alarm rendering (leaf nodes are individual conditions for native alarms
 ### Flow Debugger (Flow Debugger policy; Live run = Deployment Role)
 - **`/deployment/flow-debugger`** (nav: Deployment → Flow Debugger; design `docs/plans/2026-09-05-flow-debugger-design.md`, plan `docs/plans/2026-09-05-flow-debugger.md`). Runs one entry point with operator-supplied inputs and renders every step the run passes through as a **four-lane swimlane** (Central / Site / Tags / **External**) — request, route call, site script run, attribute writes, attribute waits, **outbound API / database / notification calls**, response — each node carrying its input, output, duration and outcome; a tabbed detail panel (Input · Output · Writes *or* Lifecycle · Timing, plus a *Where this ran* column) opens on the selected node with `Open in Debug View` (script entries, where the instance is known) and `Audit rows (n)` (→ `/audit/log?executionId=`) drill-ins.
 - **Two modes.** *Live* is a real run — the method script executes on the active central node with tracing on, or a real attribute write goes through the routed-write path and the site's triggered run is polled back — audited like any other call. *Replay* executes nothing: it rebuilds the flow from an existing execution's `ScriptTrace` audit rows plus its `ApiOutbound` / `DbOutbound` / `Notification` rows (`?executionId=` drill-in from the Audit Log drawer's and the Execution Chain page's **Open in Flow Debugger** actions).
-- **External lane (v1.1, plan `docs/plans/2026-09-06-flow-debugger-outbound-calls.md`).** Every `ExternalSystem.Call/CachedCall`, `Database.*` and `Notify.Send` a traced run makes is a node on the fourth lane — kinds `ApiCall` / `DbCall` / `Notify` (eyebrows `API CALL` / `DATABASE` / `NOTIFY`), title = the system.method / connection / list, a status pill (`Ok` / `Pending` / `Parked` / `Failed`) plus `sync` | `cached` | `notify`. **One node per operation:** a cached call's or notification's later lifecycle rows (Forwarded → Attempted → Delivered / Parked, written minutes later by the S&amp;F forwarder or the Notification Outbox) fold into the node (`FlowStep.Lifecycle`, a Lifecycle tab in the detail panel with *Delivered by*) instead of drawing four boxes. A sync call sits in the execution chain; a cached call or notification hangs off it on a dashed **async** connector, and a trigger cascade's spawn edge carries a bolt marker. A Live run returns only the rows the run itself emitted, so a graph left with `Pending` nodes **refreshes itself** through the Replay command every 5 s for up to 2 min (page constants), and a *Refresh outcomes* button re-reads on demand in either mode; the state chip stays *Completed* — pending outbound work is not a failed run. A refresh **merges** the re-read rows into the run's known rows by `EventId` (fresh copy wins) and rebuilds the graph from the union, so it only ever adds nodes: the site's outbound rows reach central's audit store by telemetry seconds after the run returned them inline, and a Replay read taken in between would otherwise erase an already-drawn node (observed on the rig 2026-09-06 with a resolved cached DB write). The union is exact because the inline rows are the very `AuditEvent` objects the site writer persists. **v1.2 (follow-ups plan `docs/plans/2026-09-06-flow-debugger-followups.md`, register row 111 closed):** a folded node carries its `CorrelationId` (`FlowStep.CorrelationId` — the `TrackedOperationId` / `NotificationId`), so the detail panel deep-links to **`/site-calls/report?correlationId=<id>`** / **`/notifications/report?correlationId=<id>`** (*Open in Site Calls* / *Open in Notification report*; both pages accept that query, pre-filter to the one row through an additive per-id query filter — `SiteCallQueryRequest.TrackedOperationIdFilter` / `NotificationOutboxQueryRequest.NotificationIdFilter` — show a removable *Operation* / *Notification* pill and auto-open the row's detail modal; note `NotificationId` is minted as a Guid in **`N` form** — no dashes — so the Notify link passes `N` and the report page normalises any Guid-shaped value to `N`, while `TrackedOperationId` is a `varchar(36)` `D` string and the Site Calls filter binds a `varchar` parameter for the PK seek), and a **`Parked` node offers Retry / Discard in place**: the same site-scope re-check, confirm dialog (Discard = danger) and central→site / Notification Outbox relay the report pages use (`IFlowDebugService.RetryOutboundAsync` / `DiscardOutboundAsync` → `CommunicationService`), then the page re-polls Replay (5 s / 2 min) until the node leaves `Parked`. **Prediction is async-safe:** `FlowDebugService.PredictMethodAsync` resolves route targets by a resolve-and-rewalk loop — its original blocking resolver deadlocked the whole Blazor circuit on the renderer sync context the moment a method routing to a site script was chosen (found 2026-09-06; pinned by a single-thread-pump unit test and the Playwright `FlowDebuggerTests`, which log in through the fixture and run a Live run of an ephemeral method in a real browser).
+- **External lane (v1.1, plan `docs/plans/2026-09-06-flow-debugger-outbound-calls.md`).** Every `ExternalSystem.Call/CachedCall`, `Database.*` and `Notify.Send` a traced run makes is a node on the fourth lane — kinds `ApiCall` / `DbCall` / `Notify` (eyebrows `API CALL` / `DATABASE` / `NOTIFY`), title = the system.method / connection / list, a status pill (`Ok` / `Pending` / `Parked` / `Failed`) plus `sync` | `cached` | `notify`. **One node per operation:** a cached call's or notification's later lifecycle rows (Forwarded → Attempted → Delivered / Parked, written minutes later by the S&amp;F forwarder or the Notification Outbox) fold into the node (`FlowStep.Lifecycle`, a Lifecycle tab in the detail panel with *Delivered by*) instead of drawing four boxes. A sync call sits in the execution chain; a cached call or notification hangs off it on a dashed **async** connector, and a trigger cascade's spawn edge carries a **bolt badge on the connector's riser** — the edge itself keeps an ordinary arrowhead (the bolt was the arrowhead until 2026-09-08, and on the upward Tags→Site hop it read as a broken arrow). The spawn edge starts at the parent's **last write of the attribute the child's `triggerAttribute` names** (`FlowGraphBuilder`); only when the child names no attribute, or the parent never wrote it, does the timestamp rule (last non-async parent step at or before the child) decide — a burst of writes landing in one millisecond used to draw the cascade from the last of them rather than the one that fired it. A Live run returns only the rows the run itself emitted, so a graph left with `Pending` nodes **refreshes itself** through the Replay command every 5 s for up to 2 min (page constants), and a *Refresh outcomes* button re-reads on demand in either mode; the state chip stays *Completed* — pending outbound work is not a failed run. A refresh **merges** the re-read rows into the run's known rows by `EventId` (fresh copy wins) and rebuilds the graph from the union, so it only ever adds nodes: the site's outbound rows reach central's audit store by telemetry seconds after the run returned them inline, and a Replay read taken in between would otherwise erase an already-drawn node (observed on the rig 2026-09-06 with a resolved cached DB write). The union is exact because the inline rows are the very `AuditEvent` objects the site writer persists. **v1.2 (follow-ups plan `docs/plans/2026-09-06-flow-debugger-followups.md`, register row 111 closed):** a folded node carries its `CorrelationId` (`FlowStep.CorrelationId` — the `TrackedOperationId` / `NotificationId`), so the detail panel deep-links to **`/site-calls/report?correlationId=<id>`** / **`/notifications/report?correlationId=<id>`** (*Open in Site Calls* / *Open in Notification report*; both pages accept that query, pre-filter to the one row through an additive per-id query filter — `SiteCallQueryRequest.TrackedOperationIdFilter` / `NotificationOutboxQueryRequest.NotificationIdFilter` — show a removable *Operation* / *Notification* pill and auto-open the row's detail modal; note `NotificationId` is minted as a Guid in **`N` form** — no dashes — so the Notify link passes `N` and the report page normalises any Guid-shaped value to `N`, while `TrackedOperationId` is a `varchar(36)` `D` string and the Site Calls filter binds a `varchar` parameter for the PK seek), and a **`Parked` node offers Retry / Discard in place**: the same site-scope re-check, confirm dialog (Discard = danger) and central→site / Notification Outbox relay the report pages use (`IFlowDebugService.RetryOutboundAsync` / `DiscardOutboundAsync` → `CommunicationService`), then the page re-polls Replay (5 s / 2 min) until the node leaves `Parked`. **Prediction is async-safe:** `FlowDebugService.PredictMethodAsync` resolves route targets by a resolve-and-rewalk loop — its original blocking resolver deadlocked the whole Blazor circuit on the renderer sync context the moment a method routing to a site script was chosen (found 2026-09-06; pinned by a single-thread-pump unit test and the Playwright `FlowDebuggerTests`, which log in through the fixture and run a Live run of an ephemeral method in a real browser).
 - **Authorization (arch-review F3).** The page is `RequireFlowDebugger` — `AuthorizationPolicies.FlowDebuggerAccessRoles` = Deployer, Administrator, Viewer — so an auditor can open it and Replay a past execution without the ability to run anything, and `FlowDebugReplayCommand` accepts the same set. **Everything that executes stays Deployer-only:** the three run commands (`FlowDebugRunMethodCommand` / `FlowDebugRunScriptCommand` / `FlowDebugRunValueChangeCommand`), the Live entry-point controls, the parked-node Retry/Discard actions and the `?methodId=` / `?instanceId=` / `?script=` drill-ins; for a non-Deployer the page pins itself to Replay mode.
 - **Two entry points** (script entry redesigned 2026-09-08, `docs/plans/2026-09-08-flow-debugger-script-entry-design.md`). An inbound API method (inputs form generated from the method's `ParameterDefinitions`, values coerced by declared type) or a **site script** (Site → Instance → Script pickers, site-scope filtered): a script whose trigger is ValueChange or Conditional shows one *New value for `<attribute>`* field, with the attribute derived from the script's own trigger configuration rather than picked; every other script kind (Call, Interval, Expression, or no trigger) shows a `ParameterValueForm` generated from the script's `ParameterDefinitions`, or a "this script takes no parameters" note when there are none. A method-entry Live run is additionally site-scoped **at route time** on the server (`RouteHelper.WithSiteScope` → `SITE_SCOPE_DENIED`, arch-review F2), so an operator cannot reach a site outside their scope by choosing a method that routes there.
 - **Predicted graph first.** Choosing an entry point renders the statically predicted shape (`FlowShapePredictor`, Script Analysis REQ-SA-7) before anything runs — nodes whose target depends on inputs render dashed; after a run, predicted nodes the run never produced render greyed.