feat: filter inbounds and clients by node (#4997)

Multi-node panels had no way to narrow the inbounds or clients lists to
a single node. Add a node filter to both pages:

- Inbounds: a toolbar select (All / Local / each node) that filters the
  list client-side; shown only when the panel has nodes or node-attached
  inbounds.
- Clients: a Nodes multi-select in the filter drawer. Node selections
  are mapped onto inbound IDs client-side and fed through the existing
  inbound CSV paging parameter, so the paging backend is untouched; an
  impossible id (-1) is sent when no inbound matches so the filter
  yields an honest empty result. InboundOption now carries nodeId to
  make the mapping possible.

The local panel is selectable via a 0 sentinel (inbounds without a
nodeId). New i18n keys in all 13 locales.

frontend/src/generated/schemas.ts

@@ -1433,6 +1433,11 @@ export const SCHEMAS: Record<string, unknown> = {
         "example": 1,
         "type": "integer"
       },
+      "nodeId": {
+        "description": "Hosting node; nil for this panel's own inbounds. Lets the clients\npage map a node filter onto inbound IDs (#4997).",
+        "nullable": true,
+        "type": "integer"
+      },
       "port": {
         "example": 443,
         "type": "integer"