Update configuration and enhance newsletter generation features

- Change WIKI_API_URL in .env.example and config to point to the new API endpoint.
- Set COOKIE_SECURE to false for local development in .env.example and config.
- Improve the newsletter generation logic to handle new and edited articles separately.
- Add display options for showing date, user, and category in the newsletter output.
- Enhance error handling for Wiki API requests and update templates for better user feedback.
- Update CSS for new UI elements and improve overall layout in dashboard and login pages.

app/static/css/main.css

@@ -9,6 +9,17 @@ label { display: grid; gap: 0.3rem; font-weight: 600; }
 input, button, textarea { font: inherit; padding: 0.55rem; }
 textarea { width: 100%; resize: vertical; }
 button { width: fit-content; background: #1b5dbf; color: #fff; border: 0; border-radius: 4px; cursor: pointer; }
+.btn-secondary { background: #334155; }
+.copy-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 0.6rem; margin-bottom: 0.75rem; }
+.copy-status { font-size: 0.92rem; color: #64748b; }
+.copy-status.success { color: #027a48; }
+.copy-status.error { color: #b42318; }
+.newsletter-preview-frame { width: 100%; min-height: 520px; border: 1px solid #dde3ef; border-radius: 6px; background: #fff; }
+.hidden-source { display: none; }
 table { width: 100%; border-collapse: collapse; }
 th, td { border-bottom: 1px solid #e6ebf4; text-align: left; padding: 0.55rem; vertical-align: top; }
 .checkbox { display: flex; align-items: center; gap: 0.45rem; font-weight: 500; }
+.display-options { border: 1px solid #dde3ef; border-radius: 6px; padding: 0.75rem; display: grid; gap: 0.45rem; }
+.display-options legend { font-weight: 600; padding: 0 0.25rem; }
+.error { color: #b42318; background: #fef3f2; border: 1px solid #fecdca; padding: 0.6rem; border-radius: 4px; margin: 0 0 0.75rem; }
+.hint { color: #64748b; font-size: 0.92rem; margin: 0 0 0.6rem; }