Bug 1: `cookies clear` printed 'Request log cleared' instead of 'Cookies cleared'
because the output handler matched the generic `{ cleared: true }` response shape
without checking the action context. Now uses the `action` parameter to distinguish
`cookies_clear` from `requests --clear`.
Bug 2: `tab close` printed 'Browser closed' instead of 'Tab closed' because the
output handler matched the generic `{ closed: ... }` response shape without checking
the action context. Now uses the `action` parameter to distinguish `tab_close` from
`close` (full browser close).
Closes#556
Giulio Leone
b304a4188c