feat(stealth): adaptive anti-bot detection drives humanize level (v2)

After each navigation, probe the loaded page for known behavioural anti-bot
vendor fingerprints — cookies (_abck/Akamai, _px/PerimeterX, datadome,
reese84/Imperva, …), script URLs, and window globals — and escalate this
session to HumanizeLevel::Human when one is present, else fall back to the Off
baseline. So ordinary sites run at full speed (instant clicks) and only pages
actually guarded by behavioural detection pay for human-like motion.

`AGENT_BROWSER_HUMANIZE` still forces a fixed level and short-circuits the probe.
Best-effort: a failed probe leaves the level unchanged. Verified end-to-end
(headless --launch): a HUMANIZE=human click on example.com traverses the curved
trajectory and lands correctly (→ iana.org), identical outcome to Off.

cli/src/native/actions.rs

@@ -23,6 +23,7 @@ use super::cdp::types::{
 use super::cookies;
 use super::diff;
 use super::element::RefMap;
+use super::humanize;
 use super::inspect_server::InspectServer;
 use super::interaction;
 use super::network::{self, DomainFilter, EventTracker};
@@ -2512,7 +2513,49 @@ async fn handle_navigate(cmd: &Value, state: &mut DaemonState) -> Result<Value,
     state.ref_map.clear();
     state.iframe_sessions.clear();
     state.active_frame_id = None;
-    mgr.navigate(url, wait_until).await
+    let result = mgr.navigate(url, wait_until).await?;
+    // Adaptive humanize: sample the freshly loaded page for known behavioural
+    // anti-bot vendors and escalate this session to Human if any are present.
+    detect_and_set_humanize(mgr).await;
+    Ok(result)
+}
+
+/// After navigation, probe the page for known anti-bot vendor fingerprints
+/// (cookies / script URLs / `window` globals) and set this session's humanize
+/// level accordingly — `Human` when a vendor is detected, else the `Off`
+/// baseline. Best-effort: any failure leaves the level unchanged. Skipped when
+/// `AGENT_BROWSER_HUMANIZE` is set, since the override always wins and the probe
+/// would be wasted work.
+async fn detect_and_set_humanize(mgr: &BrowserManager) {
+    if std::env::var("AGENT_BROWSER_HUMANIZE").is_ok() {
+        return;
+    }
+    let js = r#"(() => { try {
+        const cookies = document.cookie.split(';').map(c => c.trim().split('=')[0]).filter(Boolean);
+        const scripts = Array.from(document.scripts, s => s.src || '').filter(Boolean);
+        const re = /_px|bmak|_abck|datadome|reese84|kpsdk|incap_ses|visid_incap|akam/i;
+        const globals = Object.getOwnPropertyNames(window).filter(k => re.test(k));
+        return { cookies, scripts, globals };
+    } catch (e) { return {}; } })()"#;
+    let Ok(val) = mgr.evaluate(js, None).await else {
+        return;
+    };
+    let to_strings = |v: Option<&Value>| -> Vec<String> {
+        v.and_then(|v| v.as_array())
+            .map(|a| {
+                a.iter()
+                    .filter_map(|x| x.as_str().map(String::from))
+                    .collect()
+            })
+            .unwrap_or_default()
+    };
+    let signals = humanize::DetectSignals {
+        cookie_names: to_strings(val.get("cookies")),
+        script_urls: to_strings(val.get("scripts")),
+        window_globals: to_strings(val.get("globals")),
+    };
+    let level = humanize::detect_level(&signals, humanize::HumanizeLevel::Off);
+    humanize::set_detected_level(level);
 }
 
 async fn handle_url(state: &DaemonState) -> Result<Value, String> {