#211 follow-up: the raw-scrape fallback must carry the pane, not just the matched line

The normal backend-error path appends the pane tail to the failure reason on
purpose (fleetd#164): the BACKEND_ERROR pattern is a heuristic, and a member
that reported *about* an error while forgetting fleet_reply matches it too, so
dropping the rest of the pane destroys the report.

The new raw-scrape fallback did not do that. It matters more there, not less:
the fallback only runs when the trimmed assistant block was empty, so the raw
scrape is the ONLY copy of whatever the member managed to say. A lead read the
matched line and nothing else.

Clipped to the same cap the normal path uses, since a raw screen has no
boundary trimming to bound its size.

The assertion was watched failing without the fix:
  AssertionFailedError: fleetd#164: the failure must carry the pane, not only
  the matched line ... expected: <true> but was: <false>

mvn clean install: Tests run: 1079, Failures: 0, Errors: 0, Skipped: 0

fleetd/src/main/java/dev/ltms/fleet/inject/CompletionResolver.java

@@ -355,7 +355,12 @@ public final class CompletionResolver implements TurnListener {
         }
         String backendError = firstMatchingLine(raw, BACKEND_ERROR);
         if (backendError != null) {
-            fail(target, turn, "member " + target + " ended on a backend error: " + backendError);
+            // Carry the pane, not just the matched line — the same fleetd#164 rule the normal path
+            // above applies. Here it matters more, not less: the trimmed block was empty, so the raw
+            // scrape is the ONLY copy of whatever the member managed to say. Clipped to the same cap
+            // the normal path uses, since a raw screen has no boundary trimming to bound it.
+            fail(target, turn, "member " + target + " ended on a backend error: " + backendError
+                    + "\n--- pane tail ---\n" + clip(raw));
             return true;
         }
         return false;

fleetd/src/test/java/dev/ltms/fleet/inject/CompletionResolverTest.java

@@ -682,6 +682,12 @@ class CompletionResolverTest {
                 "classified BACKEND_ERROR from the raw scrape even though the trimmed block was empty");
         assertTrue(waiter.getNow(null).text().contains("API Error: 400 invalid request body"),
                 "the failure carries the matched line: " + waiter.getNow(null).text());
+        assertTrue(waiter.getNow(null).text().contains("--- pane tail ---"),
+                "fleetd#164: the failure must carry the pane, not only the matched line — with an "
+                        + "empty trimmed block the raw scrape is the only copy of what the member said: "
+                        + waiter.getNow(null).text());
+        assertTrue(waiter.getNow(null).text().contains("╭"),
+                "the carried pane is the raw scrape, chrome included: " + waiter.getNow(null).text());
     }
 
     @Test