feat(guards): add in-function opinionated guards and CachyOS cleanup

C1 shadows (rm, cat, ls, less, du, bash, top, ping, ssh, rg, mkdir,
help) fall back to the bare command when __fish_config_op_aliases is
falsy; rm falls back to exact 'command rm' with no wrapper. C2 gates
the auto-venv PWD hook. C3 gates smart_exit (composing with Task #4
logging), fish_right_prompt, and all six expand_bang_*/expand_typo_sub
functions atomically with the bang-bang system. C4 integration commands
(spwin, tab, split, hist, logs, upgrade) refuse with a colored stderr
error when disabled. config.fish now also strips the CachyOS distro
config's own bang-bang bindings, history override, and alias opinions
per category, restoring fish stock functions where they exist.

functions/smart_exit.fish

@@ -20,6 +20,13 @@
 # EXAMPLE
 #   smart_exit --no-log
 function smart_exit --description 'Capture colorized scrollback before exiting, with pruning and safe overrides'
+    # Opinionated guard (C3): exit plainly when overrides are disabled.
+    # This composes with Task #4's __fish_config_enable_logging, which will
+    # gate only the scrollback capture while leaving the exit wrapper active.
+    if not __fish_config_op_enabled __fish_config_op_overrides
+        builtin exit $argv
+    end
+
     set -l options h/help n/no-log
     argparse $options -- $argv
     or return 1