youtube: don't reset visitorData / retry VISIONOS on permanent content failures

A rejected primary response triggered a visitorData cache reset (and, in the
full path, a VISIONOS retry) for ANY playability failure. But age-restricted /
geo / paid / private / premium / SoundCloud-Go+ / terminated are permanent
properties of the video — client- and visitorData-independent — so resetting +
retrying VISIONOS just churns the (visitorData-based) cache the VISIONOS path
relies on and burns a wasted /player round-trip. The feed enrich hits many such
items per refresh, so the dogfood logs showed a visitorData reset before every
age-restricted item.

Add is_permanent_content_failure() and gate on it: select_primary returns the
error immediately (no reset, no VISIONOS) for permanent failures; stream_metadata
skips the reset for them. BotDetected (the actual bot-wall), decoys, and
network/transient errors stay fully recoverable — reset + VISIONOS as before.

src/youtube/stream_extractor.rs

@@ -453,12 +453,15 @@ pub fn stream_metadata(video_id: &str) -> Result<StreamInfo, ExtractionError> {
         android_token.as_ref().map(|t| t.visitor_data.as_str()),
     )?;
 
-    // A primary-android rejection (playability failure or decoy) is exactly the
-    // symptom a poisoned visitorData would produce on the primary reel call —
-    // and since it aborts extraction the value would otherwise never self-heal.
-    // Drop the cached visitorData so the next extraction fetches a fresh one.
+    // A primary-android rejection is the symptom a poisoned visitorData would
+    // produce, so drop the cache to self-heal — but ONLY for session/transient
+    // failures (bot-wall, decoy). A permanent content property (age/geo/paid/…)
+    // is client- and visitorData-independent, so resetting on it is pointless
+    // churn — and the feed enrich hits many such items per refresh.
     if let Err(e) = check_playability_status(&player_response) {
-        stream_helper::reset_visitor_data_cache();
+        if !is_permanent_content_failure(&e) {
+            stream_helper::reset_visitor_data_cache();
+        }
         return Err(e);
     }
     if is_player_response_not_valid(&player_response, video_id) {
@@ -720,6 +723,26 @@ fn primary_response_usable(resp: &Value, video_id: &str) -> Result<(), Extractio
 /// primary_is_visionos)` for the winning client, or the ORIGINAL ANDROID error
 /// when VISIONOS also fails. `fetch_visionos` is only invoked on the fallback
 /// path (so a usable ANDROID never triggers a visionOS round-trip).
+/// A failure that a different client (VISIONOS) or a fresh visitorData cannot
+/// change — a permanent property of the video/account. For these we skip both
+/// the visitorData reset and the VISIONOS retry: they'd fail identically and
+/// only churn the visitorData cache the VISIONOS path itself depends on.
+/// `BotDetected`, decoy (`Other`), and network/transport errors stay recoverable.
+fn is_permanent_content_failure(err: &ExtractionError) -> bool {
+    matches!(
+        err,
+        ExtractionError::ContentUnavailable(
+            ContentUnavailable::AgeRestricted
+                | ContentUnavailable::GeoRestricted
+                | ContentUnavailable::Paid
+                | ContentUnavailable::Private
+                | ContentUnavailable::YoutubeMusicPremium
+                | ContentUnavailable::SoundCloudGoPlus
+                | ContentUnavailable::AccountTerminated
+        )
+    )
+}
+
 fn select_primary(
     android_result: Result<Value, ExtractionError>,
     video_id: &str,
@@ -733,6 +756,17 @@ fn select_primary(
         },
         Err(e) => e,
     };
+    // A permanent content property (age/geo/paid/private/premium/terminated)
+    // fails identically on every client — return it immediately rather than
+    // burning a visitorData reset + a second /player round-trip that VISIONOS
+    // can't recover (and which would needlessly churn the visitorData the
+    // VISIONOS path relies on).
+    if is_permanent_content_failure(&android_error) {
+        log::debug!(
+            "[{video_id}] ANDROID unusable ({android_error}); permanent content — skipping VISIONOS"
+        );
+        return Err(android_error);
+    }
     // ANDROID unusable → drop the (likely poisoned) visitorData, then try
     // VISIONOS as the primary. On any VISIONOS failure, surface the ORIGINAL
     // ANDROID error rather than the visionOS one.
@@ -1661,6 +1695,48 @@ mod tests {
         );
     }
 
+    #[test]
+    fn cascade_skips_visionos_for_permanent_content_failure() {
+        // A permanent content property (geo-restricted here) fails identically
+        // on every client → NO visitorData reset, NO VISIONOS retry; surface the
+        // original error immediately. This is the fix for the feed enrich
+        // churning visitorData on every age-restricted item.
+        let fallback_ran = std::cell::Cell::new(false);
+        let visionos_ran = std::cell::Cell::new(false);
+        let geo = json!({
+            "playabilityStatus": {
+                "status": "UNPLAYABLE",
+                "reason": "This video is not available in your country"
+            },
+            "videoDetails": {"videoId": "vid"}
+        });
+        let err = select_primary(
+            Ok(geo),
+            "vid",
+            || fallback_ran.set(true),
+            || {
+                visionos_ran.set(true);
+                Ok(ok_response("vid", 18))
+            },
+        )
+        .expect_err("a permanent content failure must not be recovered");
+        assert!(
+            matches!(
+                err,
+                ExtractionError::ContentUnavailable(ContentUnavailable::GeoRestricted)
+            ),
+            "the original permanent error must be returned, got {err:?}"
+        );
+        assert!(
+            !fallback_ran.get(),
+            "visitorData reset must NOT run for a permanent content failure"
+        );
+        assert!(
+            !visionos_ran.get(),
+            "VISIONOS must NOT be fetched for a permanent content failure"
+        );
+    }
+
     #[test]
     fn cascade_falls_back_on_android_fetch_error() {
         // A hard ANDROID fetch error (not just a playability fail) also cascades.