Merge CB-563: a clipped pane scrape says it was clipped (PR #34)

When a member ends its turn without bridge_reply, CompletionResolver scrapes
the pane and resolves the waiting send with that text. The scrape is capped at
MAX_SCRAPE_CHARS (4000), and nothing told the caller when the cap had bitten.
A delegating lead could act on a report missing its end and believe it was
complete. That happened to me today: a member's full engineering report arrived
cut at exactly 4000 characters, and the only hint was a DEBUG line reading
"(4000 chars scraped)", which reads like a size and not like a warning.

The returned text now carries a marker when, and only when, it was clipped, and
the clip is logged at WARN with the original length and the cap.

The cap itself is unchanged. The problem was silence, not the number.

The CB-115 misattribution guard still compares the unmarked clipped tail to the
unmarked baseline, and the marker is appended only afterwards. Verified in the
code, not taken on report: clip() strips before truncating and the new length
check uses the same stripped length, so there is no off-by-one either.

bridged/src/main/java/dev/ltms/bridged/inject/CompletionResolver.java

@@ -55,6 +55,9 @@ public final class CompletionResolver implements TurnListener {
     /** Cap the scraped tail so a long transcript can't return an unbounded blob. */
     static final int MAX_SCRAPE_CHARS = 4000;
 
+    private static final String CLIPPED_PANE_TAIL_MARKER =
+            "[Pane tail clipped: member did not call bridge_reply.]";
+
     private final AgentControl agents;
     private final Rendezvous rendezvous;
 
@@ -147,9 +150,14 @@ public final class CompletionResolver implements TurnListener {
             return;
         }
         String tail;
+        int originalLength = 0;
+        boolean clipped = false;
         boolean scrapeFailed = false;
         try {
-            tail = clip(lastAssistantBlock(agents.read(target, SCRAPE_SOURCE)));
+            String assistantBlock = lastAssistantBlock(agents.read(target, SCRAPE_SOURCE));
+            originalLength = assistantBlock.strip().length();
+            clipped = originalLength > MAX_SCRAPE_CHARS;
+            tail = clip(assistantBlock);
         } catch (RuntimeException e) {
             // The worker finished but we couldn't read its screen — still resolve the send so the
             // caller unblocks; an empty tail beats hanging until the caller's timeout.
@@ -169,8 +177,14 @@ public final class CompletionResolver implements TurnListener {
                     target);
             return; // keep the in-flight record: a later genuine completion still needs it
         }
-        if (rendezvous.resolveCompletion(waiter, tail)) {
+        String completion = clipped ? tail + "\n" + CLIPPED_PANE_TAIL_MARKER : tail;
+        if (rendezvous.resolveCompletion(waiter, completion)) {
             inFlight.remove(target, turn);
+            if (clipped) {
+                log.warn("completion scrape for {} clipped from {} chars to the {} char cap; "
+                                + "member did not call bridge_reply, so the pane tail is partial",
+                        target, originalLength, MAX_SCRAPE_CHARS);
+            }
             log.debug("resolved send to {} via turn-completion fallback ({} chars scraped)",
                     target, tail.length());
         }

bridged/src/test/java/dev/ltms/bridged/inject/CompletionResolverTest.java

@@ -156,6 +156,33 @@ class CompletionResolverTest {
         assertEquals("No, 391 = 17 × 23.", waiter.getNow(null).text());
     }
 
+    @Test
+    void marksAClippedCompletionPaneTail() {
+        String block = "⏺ " + "x".repeat(CompletionResolver.MAX_SCRAPE_CHARS + 1) + "\n❯ ";
+        FakeHerdr herdr = new FakeHerdr().readText(block);
+        Rendezvous rendezvous = new Rendezvous();
+        CompletionResolver resolver = new CompletionResolver(new AgentControl(herdr), rendezvous);
+
+        var waiter = rendezvous.open("term_a");
+        resolver.resolve("term_a", new CompletionResolver.InFlight(waiter, null));
+
+        assertEquals("x".repeat(CompletionResolver.MAX_SCRAPE_CHARS)
+                        + "\n[Pane tail clipped: member did not call bridge_reply.]",
+                waiter.getNow(null).text());
+    }
+
+    @Test
+    void leavesAnUnclippedCompletionPaneTailUnmarked() {
+        FakeHerdr herdr = new FakeHerdr().readText("⏺ complete report\n❯ ");
+        Rendezvous rendezvous = new Rendezvous();
+        CompletionResolver resolver = new CompletionResolver(new AgentControl(herdr), rendezvous);
+
+        var waiter = rendezvous.open("term_a");
+        resolver.resolve("term_a", new CompletionResolver.InFlight(waiter, null));
+
+        assertEquals("complete report", waiter.getNow(null).text());
+    }
+
     @Test
     void resolvesSynchronouslyBeforePostTurnContextClearing() {
         FakeHerdr herdr = new FakeHerdr().readText("⏺ previous answer\n❯ ");
@@ -177,7 +204,8 @@ class CompletionResolverTest {
         // block while resolve compares against a clip()'d tail. For a block longer than MAX_SCRAPE_CHARS
         // the two capped representations differ even when the pane never changed, so the CB-115
         // byte-identical guard failed to fire and a stale completion could resolve the send. Both sides
-        // must clip identically; here an unchanged >cap block on rapid back-to-back turns stays suppressed.
+        // must clip identically. The returned-text marker is added only after this comparison, so an
+        // unchanged >cap block on rapid back-to-back turns still stays suppressed.
         String longBlock = "⏺ " + "x".repeat(CompletionResolver.MAX_SCRAPE_CHARS + 500) + "\n❯ ";
         FakeHerdr herdr = new FakeHerdr().readText(longBlock);
         Rendezvous rendezvous = new Rendezvous();