feat: detached-runs monitor page (T3 parity)

New Runs sidebar destination listing detached invocations (detach:true)
with phase, current step, project and a Cancel button while
pending/running. Workspace-scoped like Audit/Approvals, polls every 2s.
Detached runs are opt-in (detached.enabled) — the empty state explains
how to enable them. Inline help doc DE+EN. DetachedRun model +
listDetachedRuns/cancelDetachedRun in HubService, backed by the SDK's
listInvocations()/cancelInvocation(). flutter analyze clean; 29 tests
green (sidebar Y-stability updated for the new destination, model
mapping unit-tested).

Screenshot verification (light+dark) deferred — shared desktop in use.

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

lib/l10n/app_en.arb

@@ -1706,5 +1706,22 @@
   "federationEnrollmentHint": "Hand the token to the satellite operator over a secure channel. The bundled CA authenticates the satellite's first connect.",
   "workspaceAll": "All projects",
   "workspaceSwitcherTooltip": "Workspace — filters this view and stamps new runs with the selected project",
-  "workspaceProtectedHint": "Protected: logically separated in the shared hub — no hard process barrier. Critical engagements use a sealed area."
+  "workspaceProtectedHint": "Protected: logically separated in the shared hub — no hard process barrier. Critical engagements use a sealed area.",
+  "runsTitle": "Runs",
+  "runsReloadTooltip": "Reload the runs list",
+  "runsEmptyTitle": "No detached runs",
+  "runsEmptyHint": "Runs submitted with detach stay here until they finish. Detached invocations are opt-in — enable detached.enabled in the operator config to use them.",
+  "runsCancelButton": "Cancel",
+  "runsCancelSignalled": "Cancel signalled for {flow}.",
+  "@runsCancelSignalled": {"placeholders": {"flow": {"type": "String"}}},
+  "runsCancelTooLate": "The run had already finished — nothing to cancel.",
+  "runsCurrentStep": "Step: {step}",
+  "@runsCurrentStep": {"placeholders": {"step": {"type": "String"}}},
+  "runsPhasePending": "Pending",
+  "runsPhaseRunning": "Running",
+  "runsPhaseSucceeded": "Succeeded",
+  "runsPhaseFailed": "Failed",
+  "runsPhaseCancelled": "Cancelled",
+  "runsPhaseUnknown": "Unknown",
+  "navRuns": "Runs"
 }