feat: ping through agent — send ICMP ping from workstation via agent

Adds a ping tool in the Equipment page workstation card (visible when
agent is online). User enters an IP/hostname, the request goes through
the PMS backend → WebSocket → agent → executes ping -n 4, returns
raw output displayed in a monospace block.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/routes/workstations.ts

@@ -343,6 +343,23 @@ const workstationRoutes: FastifyPluginAsync = async (fastify) => {
     },
   )
 
+  // ── POST /api/hotels/:slug/workstations/:id/ping ────────────────────────────
+  fastify.post<WsParam & { Body: { host: string } }>(
+    '/api/hotels/:slug/workstations/:id/ping',
+    { onRequest: [fastify.authenticate] },
+    async (req, reply) => {
+      const { id } = req.params
+      const { host } = req.body
+      if (!host?.trim()) return reply.code(400).send({ error: 'host required' })
+      try {
+        const result = await sendCommandAndWait(id, { type: 'ping_host', host: host.trim() }, 20000) as { ok: boolean; output?: string; error?: string }
+        return result
+      } catch (err) {
+        return reply.code(502).send({ ok: false, error: err instanceof Error ? err.message : 'Ошибка' })
+      }
+    },
+  )
+
   // ── POST /api/hotels/:slug/workstations/update-all ──────────────────────────
   fastify.post<SlugParam>(
     '/api/hotels/:slug/workstations/update-all',