fuzz: log corpus size and delta after each fuzz target

Show the new corpus count and how many files were added, giving
visibility into which targets are discovering new coverage.

AI tools were used in preparing this commit.

Author: joostjager

fuzz/ci-fuzz.sh

@@ -53,7 +53,9 @@ for TARGET in src/bin/*.rs; do
 	fi
 	export HFUZZ_RUN_ARGS
 	cargo --color always hfuzz run $FILE
-	log_time "Finished $FILE"
+	NEW_CORPUS_COUNT=$(find "$CORPUS_DIR" -type f 2>/dev/null | wc -l)
+	DELTA=$((NEW_CORPUS_COUNT - CORPUS_COUNT))
+	log_time "Finished $FILE (corpus: $NEW_CORPUS_COUNT, delta: +$DELTA)"
 	if [ -f hfuzz_workspace/$FILE/HONGGFUZZ.REPORT.TXT ]; then
 		cat hfuzz_workspace/$FILE/HONGGFUZZ.REPORT.TXT
 		for CASE in hfuzz_workspace/$FILE/SIG*; do