feat(frontend): add API client, layout, and routing

- Create Axios-based API client with sources, jobs, and dashboard endpoints
- Add responsive Layout component with navigation sidebar
- Set up React Router with Dashboard, Backups, and Settings routes
- Configure TanStack Query provider with default options
- Use lucide-react for navigation icons

frontend/node_modules/@babel/plugin-transform-react-jsx-self/LICENSE

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+MIT License
+
+Copyright (c) 2014-present Sebastian McKenzie and other contributors
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

frontend/node_modules/@babel/plugin-transform-react-jsx-self/README.md

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+# @babel/plugin-transform-react-jsx-self
+
+> Add a __self prop to all JSX Elements
+
+See our website [@babel/plugin-transform-react-jsx-self](https://babeljs.io/docs/babel-plugin-transform-react-jsx-self) for more information.
+
+## Install
+
+Using npm:
+
+```sh
+npm install --save-dev @babel/plugin-transform-react-jsx-self
+```
+
+or using yarn:
+
+```sh
+yarn add @babel/plugin-transform-react-jsx-self --dev
+```

frontend/node_modules/@babel/plugin-transform-react-jsx-self/lib/index.js

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+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = void 0;
+var _helperPluginUtils = require("@babel/helper-plugin-utils");
+var _core = require("@babel/core");
+const TRACE_ID = "__self";
+function getThisFunctionParent(path) {
+  let scope = path.scope;
+  do {
+    const {
+      path
+    } = scope;
+    if (path.isFunctionParent() && !path.isArrowFunctionExpression()) {
+      return path;
+    }
+  } while (scope = scope.parent);
+  return null;
+}
+function isDerivedClass(classPath) {
+  return classPath.node.superClass !== null;
+}
+function isThisAllowed(path) {
+  const parentMethodOrFunction = getThisFunctionParent(path);
+  if (parentMethodOrFunction === null) {
+    return true;
+  }
+  if (!parentMethodOrFunction.isMethod()) {
+    return true;
+  }
+  if (parentMethodOrFunction.node.kind !== "constructor") {
+    return true;
+  }
+  return !isDerivedClass(parentMethodOrFunction.parentPath.parentPath);
+}
+var _default = exports.default = (0, _helperPluginUtils.declare)(api => {
+  api.assertVersion(7);
+  const visitor = {
+    JSXOpeningElement(path) {
+      if (!isThisAllowed(path)) {
+        return;
+      }
+      const node = path.node;
+      const id = _core.types.jsxIdentifier(TRACE_ID);
+      const trace = _core.types.thisExpression();
+      node.attributes.push(_core.types.jsxAttribute(id, _core.types.jsxExpressionContainer(trace)));
+    }
+  };
+  return {
+    name: "transform-react-jsx-self",
+    visitor: {
+      Program(path) {
+        path.traverse(visitor);
+      }
+    }
+  };
+});
+
+//# sourceMappingURL=index.js.map

frontend/node_modules/@babel/plugin-transform-react-jsx-self/package.json

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+{
+  "name": "@babel/plugin-transform-react-jsx-self",
+  "version": "7.27.1",
+  "description": "Add a __self prop to all JSX Elements",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/babel/babel.git",
+    "directory": "packages/babel-plugin-transform-react-jsx-self"
+  },
+  "homepage": "https://babel.dev/docs/en/next/babel-plugin-transform-react-jsx-self",
+  "license": "MIT",
+  "publishConfig": {
+    "access": "public"
+  },
+  "main": "./lib/index.js",
+  "keywords": [
+    "babel-plugin"
+  ],
+  "dependencies": {
+    "@babel/helper-plugin-utils": "^7.27.1"
+  },
+  "peerDependencies": {
+    "@babel/core": "^7.0.0-0"
+  },
+  "devDependencies": {
+    "@babel/core": "^7.27.1",
+    "@babel/helper-plugin-test-runner": "^7.27.1",
+    "@babel/plugin-syntax-jsx": "^7.27.1"
+  },
+  "engines": {
+    "node": ">=6.9.0"
+  },
+  "author": "The Babel Team (https://babel.dev/team)",
+  "type": "commonjs"
+}