feat(shell): add bash-style history expansions and interactive keybindings

- Replicate bash bang-operations (!^, !*, !string, etc.) via abbreviations
- Add Ctrl+G for previous path head insertion
- Add Ctrl+F for interactive history substitution
- Add Ctrl+Alt+U to quickly replace command tokens
- Update README documentation for all new features

conf.d/abbr.fish

@@ -1,7 +1,12 @@
 # Copyright (C) 2026 Rootiest
 # SPDX-License-Identifier: AGPL-3.0-or-later
-
-### Abreviations ###
+#
+#          ╭──────────────────────────────────────────────────────────╮
+#          │                       Abreviations                       │
+#          ╰──────────────────────────────────────────────────────────╯
+#
+# This file contains all the abbreviations for the terminal.
+# It is sourced by Fish on startup.
 
 # Neovim
 abbr -a n nvim
@@ -232,3 +237,11 @@ abbr -a scr 'systemctl restart'
 abbr -a ssct 'sudo systemctl status'
 abbr -a sscs 'sudo systemctl start'
 abbr -a sscr 'sudo systemctl restart'
+
+### History Expansions and Substitutions ###
+abbr -a !^ --position anywhere --function expand_bang_caret
+abbr -a '!*' --position anywhere --function expand_bang_all
+abbr -a typo_sub --position anywhere --regex '\^([^^]+)\^([^^]*)' --function expand_typo_sub
+abbr -a bang_string --position anywhere --regex '![\w.-]+' --function expand_bang_string
+abbr -a bang_search --position anywhere --regex '!\?[\w.-]+\??' --function expand_bang_search
+abbr -a bang_minus_n --position anywhere --regex '!-(\d+)' --function expand_bang_minus_n

conf.d/fish_user_key_bindings.fish

@@ -0,0 +1,55 @@
+# Copyright (C) 2026 Rootiest
+# SPDX-License-Identifier: AGPL-3.0-or-later
+#
+#          ╭──────────────────────────────────────────────────────────╮
+#          │                  Fish User Key Bindings                  │
+#          ╰──────────────────────────────────────────────────────────╯
+#
+# This file defines custom key bindings for the Fish shell.
+# It is sourced by Fish on startup.
+
+# ────────────────── Bind Prewious Path Head to Ctrl+G ─────────────────
+# Bindings to insert the previous path head into the command line
+# Behaves like `!$:h` does in bash
+#
+# Example: If the previous command was `cd /usr/local/bin`
+# pressing Ctrl+G will insert `/usr/local` into the command line.
+# ──────────────────────────────────────────────────────────────────────
+
+# ──────────── Bind Interactive History Substitution to Ctrl+F ─────────
+# Bindings to perform substitution on the previous command in the history
+# Behaves like `!!:s/old/new/` does in bash
+# 
+# Example: If the previous command was `echo this is a test`
+# typing `this is/that was` and pressing Ctrl+F
+# will insert `echo that was a test` into the command line.
+# ──────────────────────────────────────────────────────────────────────
+
+# ────────── Bind Replace First Command Token to Ctrl+Alt+U ────────────
+# Strips the first command token and places cursor at start to retype it
+#
+# Example: If the current command text is `mkdir new_folder`
+# pressing Ctrl+Alt+U will change the command line to ` new_folder`
+# with the cursor at the start, allowing you to quickly change the command
+# while keeping the arguments intact.
+# To produce `cd new_folder` or `rm new_folder` etc.
+# If the current command text is empty, the previous command's first token will be used instead.
+# ──────────────────────────────────────────────────────────────────────
+
+function fish_user_key_bindings
+
+    #   ───────────────────────────── Set Bindings ─────────────────────────────
+    #
+    # Set Emacs mode bindings:
+    bind ctrl-g __insert_previous_path_head
+    bind ctrl-f __interactive_history_sub
+    bind ctrl-alt-u _replace_command_token
+
+    # Set bindings for all Vi modes:
+    # 'default' is Vi-Command, 'insert' is Vi-Insert, 'visual' is Vi-Visual
+    for mode in default insert visual
+        bind --mode $mode ctrl-g __insert_previous_path_head
+        bind --mode $mode ctrl-f __interactive_history_sub
+        bind --mode $mode ctrl-alt-u _replace_command_token
+    end
+end