fix: equipment name refresh, hostname sync from agent hello

- WorkstationCard: useEffect to sync name state when ws.name prop changes
- agent-ws: update hostname column on hello message

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

backend/src/agent-ws.ts

@@ -144,9 +144,10 @@ export const setupAgentWsRoute: FastifyPluginAsync = async (fastify) => {
         }
         if (msg.type === 'hello') {
           console.log(`[agent-ws] Hello from ${msg.agent_id} (${wsId})`)
-          if (msg.version) {
-            db.query('UPDATE workstations SET agent_version = $1 WHERE id = $2', [msg.version, wsId]).catch(() => {})
-          }
+          db.query(
+            'UPDATE workstations SET agent_version = $1, hostname = COALESCE($2, hostname) WHERE id = $3',
+            [msg.version ?? null, msg.hostname ?? null, wsId],
+          ).catch(() => {})
         }
       } catch {}
     })