feat(tui): add remaining connection manager features

Bring over the larger connection manager feature set from the original
PR: metadata fields, search, persisted sort modes, manual reorder,
usage stats, connection import/export, and richer form/detail UI.

Preserve the current PR's startup fixes and AI-era changes while
leaving repository rename churn out of this branch.

Co-authored-by: nikita42 <13642481+rekurt@users.noreply.github.com>

Author: fcoury

crates/tsql/src/app/app.rs

@@ -11,8 +11,9 @@ mod keymap;
 mod schema;
 
 pub use connections::{
-    connections_path, load_connections, save_connections, ConnectionColor, ConnectionEntry,
-    ConnectionsFile, DbKind, SslMode,
+    connections_path, export_to_path, import_from_path, load_connections, save_connections,
+    write_connections_atomic, ConnectionColor, ConnectionEntry, ConnectionsFile, DbKind,
+    ImportConflict, ImportSummary, SortMode, SslMode,
 };
 pub use keymap::{Action, KeyBinding, Keymap};
 pub use schema::{

crates/tsql/src/config/connections.rs

@@ -47,7 +47,7 @@ pub enum ConfirmContext {
     /// Closing connection form with unsaved changes.
     CloseConnectionForm,
     /// Switching to a new connection with unsaved query changes.
-    SwitchConnection { entry: ConnectionEntry },
+    SwitchConnection { entry: Box<ConnectionEntry> },
     /// Applying an in-app binary update.
     ApplyUpdate { info: UpdateInfo },
     /// Opening the AI assistant when current query editor has content.