fix: tool bugs found in review audit

repl:  env var was dead code (hardcoded 2s), empty frame gave misleading error
check-tangle: show full SBCL output on compile failure, not filtered
verify-repl: blacklist now configurable via VERIFY_REPL_EXCLUDE env var;
  regex tightened to ';; +REPL-VERIFIED:' from ';;.REPL.VERIFIED:' (ambiguous)
org-eval: 1-based indexing to match repl-block; errors on out-of-range; errors on <1

projects/repl-tool/repl

@@ -30,7 +30,7 @@ my $sock = IO::Socket::INET->new(
     PeerHost  => $HOST,
     PeerPort  => $PORT,
     Proto     => "tcp",
-    Timeout   => 2
+    Timeout   => $TIMEOUT
 ) or die "Cannot connect to $HOST:$PORT: $!\n";
 
 sub read_frame {
@@ -58,7 +58,11 @@ write_frame($sock, $msg);
 
 # Read response
 my $response = read_frame($sock);
-if ($response) {
+if (defined $response) {
+    if ($response eq "") {
+        print STDERR "Daemon returned empty response\n";
+        exit 1;
+    }
     if ($response =~ /:VALUE "([^"]*)"/s) {
         print "$1\n";
     } elsif ($response =~ /:message "([^"]*)"/s) {