feat(functions,bindings): add smart-execute, fast-cli; refactor qalc and rm

- Add _smart_execute: context-aware Ctrl+Enter that routes to qalc when
  the buffer ends with '=', or falls through to standard execute otherwise
- Refactor qalc_eval → _qalc_eval (private helper, same behavior)
- Bind Ctrl+Enter to _smart_execute in all vi modes
- Add fast-cli wrapper (fast.com speed test) and fast placeholder with
  a friendly ANSI redirect message
- Add speedtest-fast abbreviation expanding to fast-cli
- Enhance _replace_command_token to handle sudo-prefixed commands: places
  cursor at index 5 (between sudo and the replacement slot)
- Improve rm error reporting: colored output, culprit-path listing, and
  cleaned technical detail for non-missing-file errors
- Add SPDX copyright headers to cat, ld, claude-docs, claude-pr functions
- Update README: Ctrl+Enter binding, fast-cli/fast functions, speedtest-fast abbr

functions/_smart_execute.fish

@@ -0,0 +1,29 @@
+# Copyright (C) 2026 Rootiest
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+# Executes different functions based on the command line content
+function _smart_execute --description 'Execute different functions based on the command line content'
+    # Get the current command line buffer
+    set -l cmd (commandline)
+
+    # 1. Handle empty buffer (Standard Enter behavior)
+    if test -z "$cmd"
+        commandline -f execute
+        return
+    end
+
+    # 2. Dispatch based on buffer content
+    switch "$cmd"
+        case '*='
+            # If it ends in =, run qalc
+            _qalc_eval
+
+#       case 'g *'
+#           # EXAMPLE FUTURE EXTENSION
+#           _some_git_helper
+
+        case '*'
+            # Default: execute the command line as-is
+            commandline -f execute
+    end
+end