fix(editor): prevent UI redraw conflicts during editor suspend/resume

Guard against re-entrant editor launches, abort editor on Ctrl-Z,
and centralize suspend-aware redraws through prof_doupdate() to prevent
terminal corruption when SIGTSTP is received while editor is active.

Removes SIGUSR1 editor escape in favor of standard pkill <editor> recovery.

src/tools/editor.h

@@ -16,4 +16,13 @@
 
 gboolean launch_editor(gchar* initial_content, void (*callback)(gchar* content, void* data), void* user_data);
 
+void editor_emergency_kill(void); // SIGCONT+SIGTERM the editor child
+
+// TRUE if editor child is STOPPED (Ctrl-Z / :stop / gdb-attach). Does not
+// reap; g_child_watch keeps handling exit.
+gboolean editor_check_stopped(void);
+
+// Editor-session flag accessor. Used by prof_run on SIGCONT resume.
+gboolean editor_is_active(void);
+
 #endif