fix: admin action log and impersonation improvements

- Fix admin action log not displaying entries (use raw sqlite for self-join)
- Add global impersonation banner to all pages during impersonation
- Fix timestamp display in action log (convert Unix seconds to milliseconds)
- Add loginWithToken method to auth store for direct token authentication
- Fix /api/auth/me to include impersonatedBy field from JWT
- Remove duplicate impersonation code from admin page

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

src/backend/index.js

@@ -16,6 +16,7 @@ import {
 import {
   getSystemStats,
   getUserStats,
+  getAdminActions,
   impersonateUser,
   verifyImpersonation,
   stopImpersonation,
@@ -434,9 +435,15 @@ const app = new Elysia()
       return { success: false, error: 'User not found' };
     }
 
+    // Include impersonatedBy from JWT if present (not stored in database)
+    const responseUser = {
+      ...userData,
+      impersonatedBy: user.impersonatedBy,
+    };
+
     return {
       success: true,
-      user: userData,
+      user: responseUser,
     };
   })