docs: document service-level connections and Cmd+K database switcher

Author: datlechin

docs/databases/clickhouse.mdx

@@ -18,7 +18,7 @@ Click **New Connection**, select **ClickHouse**, enter host/port/credentials/dat
 | **Host** | `localhost` | |
 | **Port** | `8123` | HTTP port (not 9000 native TCP) |
 | **Username** | `default` | Set password in production |
-| **Database** | `default` | |
+| **Database** | `default` | Leave empty to browse all databases. Switch with **Cmd+K** |
 
 Uses HTTP API (HTTPS on port 8443 with SSL/TLS enabled). Cloud providers typically expose HTTP(S) only.
 
@@ -43,7 +43,7 @@ See [Connection URL Reference](/databases/connection-urls) for all parameters.
 
 ### Database Browsing
 
-After connecting, the sidebar lists all databases on the server. Expand a database to see its tables and views. Switch databases using the database switcher in the toolbar.
+After connecting, the sidebar lists all databases on the server. Expand a database to see its tables and views. Press **Cmd+K** or click the database name in the toolbar to switch.
 
 ### Table Browsing
 

docs/databases/mongodb.mdx

@@ -23,7 +23,7 @@ TablePro supports MongoDB 5.0 and later. Collections appear as tables in the sid
 | Field | Default | Notes |
 |-------|---------|-------|
 | **Hosts** | `localhost:27017` | Add multiple hosts for replica sets |
-| **Database** | - | Database name to connect to |
+| **Database** | - | Optional. Leave empty to browse all databases. Switch with **Cmd+K** |
 | **Username** | - | Leave empty for local dev without auth |
 | **Password** | - | |
 | **Auth Database** | `admin` | Database to authenticate against |

docs/databases/mssql.mdx

@@ -22,7 +22,7 @@ Run `scripts/build-freetds.sh` first. Click **New Connection**, select **SQL Ser
 | **Host** | `localhost` | |
 | **Port** | `1433` | |
 | **Username** | `sa` | SQL Server Authentication only (no Windows Auth) |
-| **Database** | - | |
+| **Database** | - | Optional. Leave empty to browse all databases. Switch with **Cmd+K** |
 
 ## Example Configurations
 

docs/databases/mysql.mdx

@@ -58,7 +58,7 @@ Same driver for both. MySQL 8.0 defaults to `caching_sha2_password` auth (vs Mar
 
 ## Features
 
-Sidebar shows all accessible databases, tables, structure (columns, indexes, foreign keys), and DDL. Full MySQL syntax support for queries:
+Sidebar shows all accessible databases, tables, structure (columns, indexes, foreign keys), and DDL. Switch databases with **Cmd+K**. Full MySQL syntax support for queries:
 
 ```sql
 -- Select with JSON

docs/databases/overview.mdx

@@ -293,13 +293,17 @@ Click the connection button again to dismiss the popover.
 
 ## Switching Databases
 
-To switch databases on the same connection:
+One connection covers every database on the server. Switch with **Cmd+K**, or click the database name in the toolbar.
 
-1. Click the database name in the toolbar (next to the connection name)
-2. Select a different database from the dropdown
-3. The sidebar updates to show the new database's tables
+### Service-level connections
 
-No need to create separate connections for each database on the same server.
+Leave the **Database** field empty when creating the connection. Works for MySQL, MariaDB, MongoDB, SQL Server, and ClickHouse. The sidebar lists every database your user can access.
+
+PostgreSQL and Redshift need an initial database. Connect to `postgres` (Redshift: `dev`), then use **Cmd+K** to switch.
+
+<Tip>
+With a restricted user, the switcher only shows databases that user has been granted access to.
+</Tip>
 
 {/* Screenshot: Database switcher */}
 <Frame caption="Database switcher in toolbar">

docs/features/keyboard-shortcuts.mdx

@@ -18,6 +18,7 @@ TablePro is keyboard-driven. Most actions have shortcuts, and most menu shortcut
 | Open history | `Cmd+Y` |
 | Settings | `Cmd+,` |
 | Quick Switcher | `Cmd+Shift+O` |
+| Switch database | `Cmd+K` |
 | Close window | `Cmd+W` |
 | Quit | `Cmd+Q` |