Add macOS and Windows agents + multi-platform install UI

- agent/skywatch-agent-macos.sh: Full macOS bash agent (launchd)
  - CPU via top -l 2, memory via vm_stat/sysctl, disk via df -P
  - Network via netstat -ib, uptime via kern.boottime, OS via sw_vers
- agent/install-agent-macos.sh: Installs macOS agent as launchd daemon
- agent/skywatch-agent-windows.ps1: PowerShell agent (Task Scheduler)
  - CPU via Win32_PerfRawData two-sample delta, memory via Win32_OperatingSystem
  - Disk via Get-PSDrive, network via Get-NetAdapterStatistics
- agent/install-agent-windows.ps1: Installs Windows agent via Task Scheduler
- server/index.js: New routes for macOS and Windows agent scripts/installers
- client/src/Agents.js: Multi-platform install panel with Linux/macOS/Windows tabs
- client/src/Agents.css: Platform tab button styles

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

client/build/static/js/main.f791418f.js.LICENSE.txt

@@ -0,0 +1,101 @@
+/*! decimal.js-light v2.5.1 https://github.com/MikeMcl/decimal.js-light/LICENCE */
+
+/**
+ * @license React
+ * react-dom-client.production.js
+ *
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+/**
+ * @license React
+ * react-dom.production.js
+ *
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+/**
+ * @license React
+ * react-jsx-runtime.production.js
+ *
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+/**
+ * @license React
+ * react.production.js
+ *
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+/**
+ * @license React
+ * scheduler.production.js
+ *
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+/**
+ * @license React
+ * use-sync-external-store-shim.production.js
+ *
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+/**
+ * @license React
+ * use-sync-external-store-shim/with-selector.production.js
+ *
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+/**
+ * @license React
+ * use-sync-external-store-with-selector.production.js
+ *
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+/**
+ * react-router v7.10.0
+ *
+ * Copyright (c) Remix Software Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE.md file in the root directory of this source tree.
+ *
+ * @license MIT
+ */
+
+/** @license React v17.0.2
+ * react-is.production.min.js
+ *
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */