sqlite: document TUI keybind for generic tool output

The TUI ships with no keybind for session.toggle.generic_tool_output
(the keymap in packages/tui/src/config/keybind.ts sets it to
keybind("none")), so users see collapsed tool cards and no output
at all unless they either open the command palette or rebind the key.

Adds a 'ctrl+t' binding to ~/.config/opencode/tui.json so toggling is
one keystroke away, and documents the palette path + the rebind path
in the README so the user has both. No plugin code change.

plugins/sqlite/README.md

@@ -262,10 +262,29 @@ id  name     age
 The same call in the web client draws the second block as a bordered
 grid and the first block as preformatted text.
 
-**TUI visibility tip:** the TUI also hides generic tool output by
+**TUI visibility tip:** the TUI hides generic tool output by default
-default (`generic_tool_output_visibility` is `false`). Toggle it on with
+(`generic_tool_output_visibility` is `false`) and ships with no
-the `session.toggle.generic_tool_output` keybind if you do not see the
+keybinding for the toggle. The fastest way to turn it on:
-output at all.
+
+1. Press `Ctrl+P` to open the command palette, type `generic`, and pick
+   *Show generic tool output*. (Toggle the same command to hide it
+   again.)
+2. Or bind a key in `~/.config/opencode/tui.json` (global) or
+   `.opencode/tui.json` (project-local). The TUI's keybind id is
+   `session_toggle_generic_tool_output`:
+
+   ```jsonc
+   {
+     "keybinds": {
+       "session_toggle_generic_tool_output": "ctrl+t"
+     }
+   }
+   ```
+
+Without either, the tool calls show as collapsed cards with only the
+input and a status icon — no output, no table, nothing to scroll. The
+state is per-session; toggling once turns it on for the rest of the
+session, and KV persists it across restarts.
 
 ## File layout