Add dedicated GUI log stream for dashboard debugging.

Capture dashboard and PTY websocket lifecycle failures in gui.log and expose it via hermes logs.

hermes_cli/logs.py

@@ -10,6 +10,7 @@ Usage examples::
     hermes logs -f                 # follow agent.log in real time
     hermes logs errors             # last 50 lines of errors.log
     hermes logs gateway -n 100    # last 100 lines of gateway.log
+    hermes logs gui -f            # follow gui.log (dashboard/pty/ws)
     hermes logs --level WARNING    # only WARNING+ lines
     hermes logs --session abc123   # filter by session ID substring
     hermes logs --component tools  # only tool-related lines
@@ -31,6 +32,7 @@ LOG_FILES = {
     "agent": "agent.log",
     "errors": "errors.log",
     "gateway": "gateway.log",
+    "gui": "gui.log",
 }
 
 # Log line timestamp regex — matches "2026-04-05 22:35:00,123" or
@@ -150,7 +152,7 @@ def tail_log(
     Parameters
     ----------
     log_name
-        Which log to read: ``"agent"``, ``"errors"``, ``"gateway"``.
+        Which log to read: ``"agent"``, ``"errors"``, ``"gateway"``, ``"gui"``.
     num_lines
         Number of recent lines to show (before follow starts).
     follow