docs: fix Terminal-look README defect, warn about wholesale .zshrc replacement

- The chsh-to-zsh behavior is real, consequential shell-changing behavior
  and doesn't belong in the "What it does NOT do" list; moved it into the
  module's prose description and noted that chsh prompts for the account
  password via PAM.
- Added a plain warning that ~/.zshrc is replaced wholesale (not merged) by
  either look, and that any existing personal customizations end up in the
  dotevo-backup directory rather than being preserved -- important ahead of
  the upcoming live test on this machine.

Addresses findings 3 and 4 from the final whole-branch review.

README.md

@@ -86,13 +86,23 @@ The Terminal-look module sets up zsh with your chosen prompt style:
 
 Both looks install the terminal prerequisites (zsh, git, curl, fzf) across Arch, Debian, Fedora, and openSUSE via their native package managers.
 
+Once a prompt style is chosen and applied, the module automatically changes
+your login shell to zsh via `chsh` (if it isn't already zsh). `chsh` will
+prompt you for your Unix account password (via PAM) when it runs.
+
+`~/.zshrc` is replaced wholesale, not merged: any existing personal
+customizations (PATH exports, environment variables, custom functions,
+aliases, etc.) in your current `.zshrc` are moved into the backup directory
+rather than preserved in the new file. Check
+`~/.config/old2026_1/dotevo-backup-<timestamp>/` afterward if you had custom
+additions you want to bring back.
+
 ### What it does NOT do
 
 - Doesn't touch an existing shell config without backing it up first
   (`~/.config/old2026_1/dotevo-backup-<timestamp>/`).
 - Doesn't add any CLI tools beyond the prompt framework and plugins
   (zsh, git, curl, fzf, and the theme/prompt files themselves).
-- Automatically changes your login shell to zsh via `chsh` (if not already zsh) — once Terminal look is selected and a prompt style is chosen, the shell change happens automatically as part of applying the configuration.
 
 ## Customize