Redact personal data before publishing as public repo

- config/git/gitconfig: replace real name, email, SSH signing key, and
  self-hosted git credential URL with placeholder values

- stages/06-scripts.sh: remove hardcoded personal email from bw login;
  CLI prompts interactively

- config/shell/zshrc.local.example: replace personal server URLs
  (Nextcloud, LiteLLM proxy), university email address, institution-
  specific Canvas LMS URL, and identifying Canvas key prefix with
  generic example.com placeholders

- TODO.md: replace personal email and Nextcloud URL in code examples
  with generic placeholders

- stages/07-uv-projects.sh: remove private org name from comment

stages/06-scripts.sh

@@ -154,7 +154,7 @@ if [ "${_do_bw_setup:-false}" = true ]; then
     info "If you have 2FA enabled, you'll be prompted for that too."
     echo "----------------------------------------"
     echo ""
-    bw login hi@julianprester.com || {
+    bw login || {
       warn "Bitwarden login failed or was cancelled."
       warn "You can run 'bw login' manually later."
     }