Add a new "Export Database" feature accessible from the sidebar
right-click menu on database/schema nodes. Generates a .sql file
containing CREATE TABLE DDL, batched INSERT statements, and
view/procedure/function source code.
Backend (database_export.rs):
- Stream-writes SQL to file with configurable batch size
- Supports all SQL database types via existing DDL/INSERT generators
- Progress events with cancellation support
- Graceful error handling (continues on per-table failures)
Frontend (DatabaseExportDialog.vue):
- Connection/database/schema selector
- Checkboxes: structure, data, objects
- Real-time progress with current table and row count
- Cancel button
Wired up through Tauri commands, Web SSE routes, and API layer.
Extract 11 composables and 5 layout components from App.vue, reducing it
from 1921 to 327 lines. Unify dialog overlay style across DialogContent
and DialogScrollContent for consistent backdrop appearance.