feat(Loader): create loader component with spinner and optional message

src/shared/ui/Loader/Loader.stories.svelte

@@ -0,0 +1,33 @@
+<script module>
+import { defineMeta } from '@storybook/addon-svelte-csf';
+import Loader from './Loader.svelte';
+
+const { Story } = defineMeta({
+    title: 'Shared/Loader',
+    tags: ['autodocs'],
+    parameters: {
+        docs: {
+            description: {
+                component: 'Spinner with optional message',
+            },
+            story: { inline: false }, // Render stories in iframe for state isolation
+        },
+    },
+    argTypes: {
+        message: {
+            control: 'text',
+            description: 'Optional message to display',
+            defaultValue: 'analyzing_data',
+        },
+        size: {
+            control: 'number',
+            description: 'Size of the spinner',
+            defaultValue: 20,
+        },
+    },
+});
+</script>
+
+<Story name="Default">
+    <Loader />
+</Story>

src/shared/ui/Loader/Loader.svelte

@@ -0,0 +1,77 @@
+<!--
+    Component: Loader
+    Displays a loading spinner with an optional message.
+-->
+<script lang="ts">
+import { fade } from 'svelte/transition';
+
+interface Props {
+    /**
+     * Icon size (in pixels)
+     * @default 20
+     */
+    size?: number;
+    /**
+     * Additional classes for container
+     */
+    class?: string;
+    /**
+     * Message text
+     * @default analyzing_data
+     */
+    message?: string;
+}
+
+let { size = 20, class: className = '', message = 'analyzing_data' }: Props = $props();
+</script>
+
+<div
+    class="absolute inset-x-0 inset-y-0 flex items-center justify-center gap-4 {className}"
+    in:fade={{ duration: 300 }}
+    out:fade={{ duration: 300 }}
+>
+    <div style:width="{size}px" style:height="{size}px">
+        <svg class="stroke-gray-900 stroke-1" viewBox="0 0 24 24" fill="none" xmlns="http://www.w3.org/2000/svg">
+            <g transform="translate(12, 12)">
+                <!-- Four corner brackets rotating -->
+                <g>
+                    <path
+                        d="M -8 -8 L -4 -8 M -8 -8 L -8 -4"
+                        stroke="currentColor"
+                        stroke-width="1"
+                        stroke-linecap="round"
+                    />
+                    <path
+                        d="M 8 -8 L 4 -8 M 8 -8 L 8 -4"
+                        stroke="currentColor"
+                        stroke-width="1"
+                        stroke-linecap="round"
+                    />
+                    <path
+                        d="M -8 8 L -4 8 M -8 8 L -8 4"
+                        stroke="currentColor"
+                        stroke-width="1"
+                        stroke-linecap="round"
+                    />
+                    <path d="M 8 8 L 4 8 M 8 8 L 8 4" stroke="currentColor" stroke-width="1" stroke-linecap="round" />
+
+                    <animateTransform
+                        attributeName="transform"
+                        type="rotate"
+                        from="0"
+                        to="360"
+                        dur="3s"
+                        repeatCount="indefinite"
+                    />
+                </g>
+            </g>
+        </svg>
+    </div>
+    <!-- Divider -->
+    <div class="w-px h-3 bg-gray-400/50"></div>
+
+    <!-- Message -->
+    <span class="font-mono text-[10px] uppercase tracking-[0.2em] text-gray-600 font-medium">
+        {message}
+    </span>
+</div>