feat(shell): add scrollback history capture on shell exit

- Add smart_exit function: captures Kitty scrollback to a timestamped
  log file on exit; --no-log/-n skips capture; auto-prunes oldest logs
  once count exceeds SCROLLBACK_HISTORY_MAX_FILES
- Wire exit → smart_exit in config.fish for interactive sessions;
  export SCROLLBACK_HISTORY_DIR and SCROLLBACK_HISTORY_MAX_FILES with
  sane defaults (~/.terminal_history and 100 respectively)
- Update cat to detect files in SCROLLBACK_HISTORY_DIR or containing
  raw ANSI escape sequences and pass them through command cat instead
  of bat, preserving color output
- Remove redundant alias rm="rm -i" from tricks.fish (superseded by
  functions/rm.fish trash-aware wrapper)
- Sync README: new Scrollback History integration section, smart_exit
  added to System functions table, cat description updated, stale rm
  Safety Wrapper entry and note removed

config.fish

@@ -70,6 +70,24 @@ set -gx SUDO_EDITOR $EDITOR
 #   Helps ensure that GPG can prompt for passphrases correctly when invoked from the terminal.
 set -gx GPG_TTY (tty)
 
+#   ────────────────────────── Scrollback History ──────────────────────────
+#   Directory where scrollback history is saved into log files.
+set -gx SCROLLBACK_HISTORY_DIR "$HOME/.terminal_history"
+#   Maximum number of scrollback history files to keep
+set -gx SCROLLBACK_HISTORY_MAX_FILES 100
+# Wire up a clean exit function that won't fire on background subshells
+if status is-interactive
+    function exit --description 'Safe interactive exit'
+        # If the smart_exit file exists in our function path, invoke it explicitly
+        if functions -q smart_exit
+            smart_exit $argv
+        else
+            # Absolute fallback to protect shell mechanics
+            builtin exit $argv
+        end
+    end
+end
+
 #   ──────────────────────────── PATH variables ────────────────────────────
 #   Adds common user bin directories to the PATH. The -mg --move option for cargo ensures that
 #   the cargo bin directory is moved to the end of the PATH, which can help avoid conflicts