feat(workflow): beoordeling escalation to teamlead after 14 days (S-14, closes #15) (#99)

## What & why

S-14: a beoordeling a behandelaar does not pick up within **14 days** escalates to the **teamlead**.

A non-interrupting `P14D` boundary timer on the `Beoordelen` user task fires an external-worker task
(`BeoordelingEscaleren`); the domain's escalation worker reassigns the still-open task's candidate group
from `behandelaar` to `teamlead`. The task keeps its identity — only who may claim it changes. The
escalation-via-external-worker decision is recorded in **ADR-0015** (proposal #98); it upholds §8.2
(the Workflow Client stays the only code that talks to Flowable) and keeps Flowable a stock image.

Closes #15

## Definition of Done

- [x] Linked Gitea issue (above).
- [x] Failing test committed before the implementation.
- [x] Implementation makes the test pass; refactor commit if structure improved.
- [x] Conventional Commits referencing the issue (`refs #NN`).
- [x] CI green — all Gitea Actions jobs.
- [x] `docker compose up` from a fresh clone reaches green health checks within 3 minutes (no new services; escalation is additive to the domain worker).
- [x] Docs updated (ADR-0015, demo note).
- [x] ADR added (`docs/architecture/adr-0015-beoordeling-escalation.md`).
- [x] Demo note in `docs/demo-script.md`.

## How it was built (TDD)

- **Workflow Client** (`IBeoordelingEscalatieClient`): acquire `BeoordelingEscaleren` jobs → find the open `Beoordelen` task in the instance → add `teamlead`/remove `behandelaar` candidate group → complete the job. Red → green.
- **Escalation drain loop** (`BeoordelingEscalatieProcessor`) + hosted `BeoordelingEscalatiePump`, mirroring the OpenZaak worker. Red → green.
- **BPMN**: non-interrupting `P14D` boundary timer on `Beoordelen` → external task → escalation end.
- **Both branches** (escalate after timeout; no-op when completed in time) covered by the `Een beoordeling escaleren` acceptance scenarios + Workflow Client unit tests.
- **Live integration**: `verify-domain` fires the timer early via Flowable's management API and asserts the reassignment to teamlead.

## Notes for reviewers

- Interface segregation: escalation is on `IBeoordelingEscalatieClient`, separate from the OpenZaak worker's `IExternalWorkerClient`.
- Reassignment is two REST hops (add teamlead, remove behandelaar); idempotent on redelivery — see ADR-0015 consequences.
- Local checks green: domain unit tests (104), acceptance (13), `dotnet format --verify-no-changes`, Release build (0 errors), **domain mutation 96.69%** (break 90). The `run-domain-check.sh` escalation path is CI-verified on verify-stack (local full-stack run is constrained here).
- `BeoordelingEscalatiePump` excluded from mutation, mirroring the existing `OpenZaakJobPump` exclusion.

Reviewed-on: #99

workflows/registratie.bpmn

@@ -15,7 +15,12 @@
        S-11 adds withdrawal: while parked at Beoordelen the citizen can trek de aanvraag in — an
        interrupting message boundary event (RegistratieIngetrokken) cancels the task and ends the
        process via a dedicated "ingetrokken" end (ADR-0014). The Workflow Client delivers the message
-       to the task's execution; the BPMN owns the cancellation path. -->
+       to the task's execution; the BPMN owns the cancellation path.
+       S-14 adds escalation: a NON-interrupting boundary timer (P14D) on Beoordelen. If a behandelaar
+       has not picked the task up within 14 days it fires a parallel token to an external-worker task
+       (BeoordelingEscaleren); the Workflow Client reassigns the still-open Beoordelen task from the
+       behandelaar group to teamlead (ADR-0015). The Beoordelen task stays open throughout — the timer
+       only changes who may claim it. -->
   <message id="Message_Ingetrokken" name="RegistratieIngetrokken"/>
 
   <process id="registratie" name="Registratie ontvangen" isExecutable="true">
@@ -45,6 +50,25 @@
     <sequenceFlow id="flow4" sourceRef="Ingetrokken" targetRef="endIngetrokken"/>
 
     <endEvent id="endIngetrokken" name="Registratie ingetrokken"/>
+
+    <!-- Escalation (S-14): non-interrupting P14D boundary timer on Beoordelen. On timeout a parallel
+         token runs EscaleerBeoordeling, an external-worker task the Workflow Client picks up to
+         reassign the still-open Beoordelen task from behandelaar to teamlead (ADR-0015). -->
+    <boundaryEvent id="EscaleerTimer" attachedToRef="Beoordelen" cancelActivity="false">
+      <timerEventDefinition>
+        <timeDuration>P14D</timeDuration>
+      </timerEventDefinition>
+    </boundaryEvent>
+
+    <sequenceFlow id="flow5" sourceRef="EscaleerTimer" targetRef="EscaleerBeoordeling"/>
+
+    <serviceTask id="EscaleerBeoordeling" name="Beoordeling escaleren"
+                 flowable:type="external-worker"
+                 flowable:topic="BeoordelingEscaleren"/>
+
+    <sequenceFlow id="flow6" sourceRef="EscaleerBeoordeling" targetRef="endEscaleren"/>
+
+    <endEvent id="endEscaleren" name="Beoordeling geëscaleerd"/>
   </process>
 
   <bpmndi:BPMNDiagram id="diagram">
@@ -83,6 +107,24 @@
         <omgdi:waypoint x="450" y="165"/>
         <omgdi:waypoint x="450" y="220"/>
       </bpmndi:BPMNEdge>
+      <bpmndi:BPMNShape id="s_escaleerTimer" bpmnElement="EscaleerTimer">
+        <omgdc:Bounds x="480" y="70" width="30" height="30"/>
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNShape id="s_escaleerBeoordeling" bpmnElement="EscaleerBeoordeling">
+        <omgdc:Bounds x="580" y="20" width="120" height="60"/>
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNShape id="s_endEscaleren" bpmnElement="endEscaleren">
+        <omgdc:Bounds x="760" y="35" width="30" height="30"/>
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNEdge id="e_flow5" bpmnElement="flow5">
+        <omgdi:waypoint x="495" y="70"/>
+        <omgdi:waypoint x="495" y="50"/>
+        <omgdi:waypoint x="580" y="50"/>
+      </bpmndi:BPMNEdge>
+      <bpmndi:BPMNEdge id="e_flow6" bpmnElement="flow6">
+        <omgdi:waypoint x="700" y="50"/>
+        <omgdi:waypoint x="760" y="50"/>
+      </bpmndi:BPMNEdge>
     </bpmndi:BPMNPlane>
   </bpmndi:BPMNDiagram>
 </definitions>