feat(commands): Quick Switcher for DB objects Ctrl/Cmd+K (CP-03) #747

Parent

#742
Depends on: CP-02 #744
Template: docs/ui-parity-and-command-palette-issues.md CP-03

Goal

Jump to a table / view / collection / saved query without walking the sidebar. Ctrl/Cmd+K (or prefix # / @ inside the palette).

Implementation

1. lib/features/command_palette/quick_switcher_dialog.dart
2. Source: cached schema of the active connection (do not hit the network on every keystroke)
3. Row: name, schema/db, kind icon, optional row count
4. Enter opens the object in the grid / explorer (same path as tree leaf tap)
5. Fuzzy filter must stay off the UI isolate for large schemas (hundreds of tables)

Acceptance

• Ctrl/Cmd+K + users + Enter opens public.users (or equivalent)
• Works for PG / MySQL / SQLite at minimum; Mongo collections + extension tables if cache exists
• Typing stays responsive with a large schema