Improve and Complete Hindi (hi) Translations for DrawDB UI

The Hindi (hi) translation file is partially complete and several keys from the English (en) source are missing. These missing entries cause fallback to English in parts of the UI.

Missing / incomplete keys include (not limited to):

- upload_fileinsert_sql
- export_saved_data
- dbml_view, tab_view
- Timeline + versions keys
- Bulk update + multiselect keys
- Relationship label / coordinate system keys

Tasks:

- Add all missing Hindi translation keys.
- Improve consistency with natural Hindi phrasing.
- Keep variable placeholders (e.g., {{tableName}}) unchanged.
- Perform a completeness check against the English source file before submitting the PR.

Checklist:

[ ] - Add missing keys
[ ] - Verify all Hindi translations
[ ] - Ensure formatting and structure match project standards