docs(readme): add Ctrl+Alt+= qalc_eval keybinding to User Bindings table

Documents the new inline Qalculate! evaluator shortcut added in the
recent config refactor, so users know it exists and how to use it.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

README.md

@@ -151,6 +151,7 @@ Beyond standard shell and FZF bindings, these custom interactive shortcuts are a
 | `Ctrl+G` | Previous Path Head | Behaves like `!$:h` in Bash. Inserts the directory part of the previous command's last argument. |
 | `Ctrl+F` | Interactive History Substitution | Behaves like `!!:s/old/new/` in Bash. Performs substitution on the previous command using `old/new` syntax. When no text is entered, prepends `sudo` to the previous command. The `old/new/n` syntax will perform substitution on the command `n` lines previous in the history. |
 | `Ctrl+Alt+U` | Replace Command Token | Strips the first token (the command) from the current line. **If the line is empty**, it pulls the previous command and strips its first token, placing the cursor at the start for a quick replacement (e.g., changing `mkdir` to `cd` while keeping the paths). |
+| `Ctrl+Alt+=` | Inline Qalculate! Evaluation | Passes the current command-line buffer to `qalc` (Qalculate!) and prints the result, then clears the buffer. Allows rapid-fire math without leaving the shell — type `150 * 1.08`, press `Ctrl+Alt+=`, and see `162` immediately. |
 
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