♻️ refactor: migrate Next.js navigation APIs to React Router for SPA (#11394)

This implements Phase 3 of LOBE-2850, establishing a dual routing architecture
for the Next.js to Vite React Router SPA migration.

## Changes

### New wrapper modules
- `src/libs/next/` - Next.js wrappers for auth pages (Link, Image, navigation, dynamic)
- `src/libs/router/` - React Router wrappers for SPA routes (Link, navigation hooks)

### Link component updates
- External links (`http://`, `https://`) → native `<a>` tags
- SPA internal routes → React Router `<Link>`
- Auth pages → Next.js `<Link>` (preserved)
- Global `src/components/Link.tsx` → smart component for ConfigProvider

### Navigation hook updates
- SPA routes use `@/libs/router/navigation` (useRouter, usePathname, useSearchParams)
- Auth pages use `@/libs/next/navigation`
- GlobalProvider uses `window.location` (outside Router context)

### Architecture
```
GlobalProvider (no Router context)
└── AppTheme + ConfigProvider
    ├── Auth pages (Next.js routing)
    └── SPA Router (BrowserRouter)
        └── SPA pages (React Router)
```

Resolves LOBE-2850

scripts/migrate-spa-navigation.ts

@@ -0,0 +1,129 @@
+#!/usr/bin/env bun
+/**
+ * Script to migrate SPA internal components from @/libs/next/navigation
+ * to React Router version hooks.
+ *
+ * For files in (main) directory:
+ * - usePathname -> @/app/[variants]/(main)/hooks/usePathname
+ * - useSearchParams -> @/app/[variants]/(main)/hooks/useSearchParams
+ * - useRouter -> @/app/[variants]/(main)/hooks/useRouter
+ *
+ * @see RFC 147: LOBE-2850 - Phase 3
+ */
+
+import { readFile, writeFile } from 'node:fs/promises';
+import { dirname, join, relative } from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+
+// Files that should be migrated to React Router version
+const SPA_FILES = [
+  // (main) directory files using @/libs/next/navigation
+  'src/app/[variants]/(main)/community/_layout/Sidebar/Header/Nav.tsx',
+  'src/app/[variants]/(main)/group/_layout/Sidebar/Header/Nav.tsx',
+  'src/app/[variants]/(main)/group/_layout/Sidebar/Topic/hooks/useTopicNavigation.ts',
+  'src/app/[variants]/(main)/group/_layout/Sidebar/Topic/hooks/useThreadNavigation.ts',
+  'src/app/[variants]/(main)/chat/_layout/Sidebar/Header/AddTopicButon.tsx',
+  'src/app/[variants]/(main)/chat/_layout/Sidebar/Header/Nav.tsx',
+  'src/app/[variants]/(main)/chat/_layout/Sidebar/Topic/hooks/useTopicNavigation.ts',
+  'src/app/[variants]/(main)/chat/_layout/Sidebar/Topic/hooks/useThreadNavigation.ts',
+  'src/app/[variants]/(main)/memory/_layout/Sidebar/Header/Nav.tsx',
+];
+
+interface MigrationResult {
+  changes: string[];
+  filePath: string;
+}
+
+async function migrateFile(relativePath: string): Promise<MigrationResult | null> {
+  const fullPath = join(__dirname, '..', relativePath);
+  const content = await readFile(fullPath, 'utf8');
+  let newContent = content;
+  const changes: string[] = [];
+
+  // Check what hooks are being imported from @/libs/next/navigation
+  const importMatch = content.match(
+    /import\s*\{([^}]+)\}\s*from\s*['"]@\/libs\/next\/navigation['"]/
+  );
+
+  if (!importMatch) {
+    console.log(`⏭️  ${relativePath} - No @/libs/next/navigation import found`);
+    return null;
+  }
+
+  const importedHooks = importMatch[1]
+    .split(',')
+    .map((s) => s.trim())
+    .filter(Boolean);
+
+  console.log(`📝 ${relativePath}`);
+  console.log(`   Imported hooks: ${importedHooks.join(', ')}`);
+
+  // Build new imports
+  const newImports: string[] = [];
+
+  for (const hook of importedHooks) {
+    if (hook === 'usePathname') {
+      newImports.push(`import { usePathname } from '@/app/[variants]/(main)/hooks/usePathname';`);
+      changes.push('usePathname -> React Router version');
+    } else if (hook === 'useSearchParams') {
+      newImports.push(
+        `import { useSearchParams } from '@/app/[variants]/(main)/hooks/useSearchParams';`
+      );
+      changes.push('useSearchParams -> React Router version');
+    } else if (hook === 'useRouter') {
+      newImports.push(`import { useRouter } from '@/app/[variants]/(main)/hooks/useRouter';`);
+      changes.push('useRouter -> React Router version');
+    } else {
+      // Keep other imports (like notFound, redirect) from next/navigation
+      console.log(`   ⚠️  Unknown hook "${hook}" - keeping original import`);
+    }
+  }
+
+  if (newImports.length === 0) {
+    console.log(`   ⏭️  No hooks to migrate`);
+    return null;
+  }
+
+  // Replace the old import with new imports
+  newContent = newContent.replace(
+    /import\s*\{[^}]+\}\s*from\s*['"]@\/libs\/next\/navigation['"];?\n?/,
+    newImports.join('\n') + '\n'
+  );
+
+  if (newContent !== content) {
+    await writeFile(fullPath, newContent, 'utf8');
+    for (const change of changes) {
+      console.log(`   ✅ ${change}`);
+    }
+    return { changes, filePath: relativePath };
+  }
+
+  return null;
+}
+
+async function main() {
+  console.log('🚀 Starting SPA navigation migration...\n');
+
+  const results: MigrationResult[] = [];
+
+  for (const file of SPA_FILES) {
+    try {
+      const result = await migrateFile(file);
+      if (result) {
+        results.push(result);
+      }
+    } catch (error) {
+      console.error(`❌ Error processing ${file}:`, error);
+    }
+  }
+
+  console.log('\n' + '='.repeat(60));
+  console.log(`📊 Migration Summary:`);
+  console.log(`   - Files processed: ${SPA_FILES.length}`);
+  console.log(`   - Files modified: ${results.length}`);
+  console.log('\n✨ SPA navigation migration complete!');
+}
+
+await main();