v4.1.0

Added

• Client#serp(q:, engine: nil, gl: nil, hl: nil, page: nil) for the new GET /serp endpoint — parsed Google search results (organic results, related searches, pagination) as a Hash. Flat 15 credits per search. Raises ArgumentError when q is blank or not a String, or when page is not an Integer >= 1 (the server also rejects it with a 400, not billed; checking client-side saves the round trip). Pages are 1–100: the server rejects a page above 100 with a 400.
• bin/smoke.rb live smoke script: asserts result shapes (not just the absence of exceptions), runs page tools with js: false on datacenter proxies (~32 credits per sweep), and redacts the API key from failure output.

Fixed

• Client#inspect and Configuration#inspect no longer print the API key; it is shown as api_key="[FILTERED]".