feat: add /reasoning reasoning visibility

docs/tools/slash-commands.md

@@ -40,6 +40,7 @@ Text + native (when enabled):
 - `/reset` or `/new`
 - `/think <level>` (aliases: `/thinking`, `/t`)
 - `/verbose on|off` (alias: `/v`)
+- `/reasoning on|off` (alias: `/reason`)
 - `/elevated on|off` (alias: `/elev`)
 - `/model <name>`
 - `/queue <mode>` (plus options like `debounce:2s cap:25 drop:summarize`)

docs/tools/thinking.md

@@ -34,6 +34,12 @@ read_when:
 - Inline directive affects only that message; session/global defaults apply otherwise.
 - When verbose is on, agents that emit structured tool results (Pi, other JSON agents) send each tool result back as its own metadata-only message, prefixed with `<emoji> <tool-name>: <arg>` when available (path/command); the tool output itself is not forwarded. These tool summaries are sent as soon as each tool finishes (separate bubbles), not as streaming deltas. If you toggle `/verbose on|off` while a run is in-flight, subsequent tool bubbles honor the new setting.
 
+## Reasoning visibility (/reasoning)
+- Levels: `on|off`.
+- Directive-only message toggles whether thinking blocks are shown as italic text in replies.
+- When enabled, any model-provided reasoning content is appended as a separate italic block.
+- Alias: `/reason`.
+
 ## Related
 - Elevated mode docs live in [`docs/elevated.md`](/tools/elevated).