Fix known-hosts trust deadlock, host key stat, and optional nozstd build

- stdout logger: release mutex while waiting on pause resume so prompt
  callbacks can log (fixes hang after trusting new hosts; known_hosts
  was written but Resume never ran).
- known hosts callback: stop borrowing the SSH dial throttle channel
  (could block or interact badly with parallel handshakes).
- host key path: use errors.Is(..., fs.ErrNotExist) for RootedPath.Stat
  wrapped errors; stat errors now fail fast instead of mis-read.
- public key path: same ErrNotExist check for authorized_keys miss.
- Build: optional DTAIL_NO_ZSTD=yes / nozstd tag for CGO-free builds;
  split zstd readers into tagged files.
- Docs/examples: firewalld note for port 2222, log prune timer+script,
  SSHBindAddress note, dserver unit disabled-by-default comment;
  firewalld helper script example.
- Regression test for stdout pause/mutex behavior.

Made-with: Cursor

1 files changed, 21 insertions, 0 deletions

diff --git a/examples/firewalld-dserver-port.sh.example b/examples/firewalld-dserver-port.sh.example
new file mode 100644
index 0000000..f10ce08
--- /dev/null
+++ b/examples/firewalld-dserver-port.sh.example
@@ -0,0 +1,21 @@
+#!/bin/bash
+# Allow inbound TCP to dserver (default port 2222) when firewalld is used.
+# Run once on the server as root, or fold into your config management.
+
+set -euo pipefail
+
+PORT="${DTAIL_FIREWALL_PORT:-2222}"
+
+if ! command -v firewall-cmd >/dev/null 2>&1; then
+	echo "firewall-cmd not found; skip or configure your firewall manually." >&2
+	exit 0
+fi
+
+if ! firewall-cmd --state >/dev/null 2>&1; then
+	echo "firewalld not running; nothing to do." >&2
+	exit 0
+fi
+
+firewall-cmd --permanent "--add-port=${PORT}/tcp"
+firewall-cmd --reload
+echo "Opened ${PORT}/tcp. Current ports: $(firewall-cmd --list-ports)"