docs(readme): document the curated shell aliases in §5 Day-to-day

List the on-by-default zsh aliases (navigation, git, nix, misc) in the
Day-to-day section so they're discoverable from the README, not just by
running `alias`. Note the doc location in the roadmap item.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

README.md

@@ -296,6 +296,32 @@ picker · `SUPER+SHIFT+T` next wallpaper · `SUPER+X` power menu ·
 clipboard history · `SUPER+Q`
 close · `SUPER+1..9` workspaces · `Print` region screenshot.
 
+Shell aliases (zsh, gated on `nomarchy.shell.enable`) — `alias` lists them
+all; the curated set:
+
+```sh
+# navigation
+..   ...   ....                 # cd up 1 / 2 / 3 levels
+
+# git
+g    gst                        # git · git status -sb
+ga   gaa                        # git add · git add -A
+gc   gcm                        # git commit · git commit -m
+gco  gsw   gb                   # checkout · switch · branch
+gd   gds                        # diff · diff --staged
+gl   glg                        # log graph (last 20 · all branches)
+gp   gpl   gf                   # push · pull · fetch --all --prune
+
+# nix  (system/home rebuilds keep their full sys-update / home-update names)
+ns   nr                         # nix shell · nix run   (e.g. ns nixpkgs#ripgrep)
+nfu  nfc                        # nix flake update · check
+nsearch    ngc                  # nix search nixpkgs · nix-collect-garbage -d
+
+# misc
+path                            # print $PATH, one entry per line
+reload                          # exec zsh (reload the shell)
+```
+
 ## 6. Extending
 
 - **New theme:** drop a JSON into `themes/` (schema = any existing preset),