feat: eval prints its origin URL, type --focused, AGENT_BROWSER_HUMANIZE bogus warn

- eval now prints `eval @ <url>` to stderr (stdout stays the raw value) so an
  agent can catch tab drift — e.g. a logged-in fetch that hit the wrong origin —
  before trusting the result. Mitigates the issue #2/#3 P0 safety concern. (eval
  already returned the origin; the default output just never surfaced it.)
- `type --focused <text>`: type into the currently-focused element with no
  selector, for custom widgets that move focus to a hidden input (issue #2 P3).
- AGENT_BROWSER_HUMANIZE set to an unrecognized value now warns once (like the
  --humanize flag) instead of being silently ignored (Hermes #3).

cli/src/output.rs

@@ -358,6 +358,16 @@ pub fn print_response_with_opts(resp: &Response, action: Option<&str>, opts: &Ou
         }
         // Eval result
         if let Some(result) = data.get("result") {
+            // Surface which page the eval actually ran on — to stderr, so it
+            // never corrupts the parsed value on stdout. Lets an agent catch tab
+            // drift (commands landing on the wrong tab) before trusting a result,
+            // e.g. a logged-in `fetch` that hit the wrong origin. (In
+            // content-boundaries mode the origin is already in the banner.)
+            if !opts.content_boundaries {
+                if let Some(o) = origin.filter(|o| !o.is_empty()) {
+                    eprintln!("eval @ {o}");
+                }
+            }
             let formatted = serde_json::to_string_pretty(result).unwrap_or_default();
             print_with_boundaries(&formatted, origin, opts);
             return;