Replace Hack Club example emails with KiwiHacks ones

[N1k0s1]

Closes #3.

The signup/login email placeholder, the API docs examples, and the mailer previews all still showed Hack Club addresses and the Orpheus mascot. Every example address is now kiki@kiwihacks.org (Kiki is the KiwiHacks mascot), and the preview identity is renamed to match.

User-visible

Where	Was	Now
config/locales/en.yml — signup + login email field	orpheus@dino.mail	kiki@kiwihacks.org
app/views/email_changes/new.html.erb — new-email field	new@electronic.mail	kiki@kiwihacks.org
app/views/docs/api.md.erb — /docs/api	orpheus@example.com	kiki@kiwihacks.org
app/views/static_pages/external_api_docs.html.erb — /api/external	nora@hackclub.com	kiki@kiwihacks.org

Mailer previews

Six files under spec/mailers/previews/ — first_name: "Orpheus" → "Kiki", orpheus@hackclub.com → kiki@kiwihacks.org. The email-change preview's destination address becomes kiki.new@kiwihacks.org so it stays distinct from the old address.

Test data

spec/factories/identities.rb, spec/models/identity/email_change_request_spec.rb, and spec/requests/api/external/whoami_spec.rb — fixture addresses and the whoami CORS origin (https://program.hackclub.com → https://program.kiwihacks.org) now use a domain we own.

Testing

• bundle exec rspec — 287 examples, 36 failures, byte-identical to the failure list on the unmodified branch. All pre-existing, none in files this PR touches.
• bundle exec rspec -O /dev/null spec/models/identity/email_change_request_spec.rb spec/requests/api/external/whoami_spec.rb — 44 examples, 0 failures. (-O /dev/null is needed because .rspec's --pattern otherwise overrides file arguments.)
• bin/lint clean on the changed files.
• Rendered locally against bin/rails s: /login, /signup, and /docs/api all serve kiki@kiwihacks.org; all six mailer previews return 200 with no Orpheus or hackclub.com left in the bodies.

Not verified locally

• /api/external 500s on main and on this branch alike — app/views/layouts/backend.html.erb:22 calls an undefined breadcrumbs. Unrelated to this change, but it means that page's example could not be eyeballed.
• /email_changes/new sits behind step-up auth, and the login code is delivered via Loops, which isn't configured in local dev. The placeholder there is a plain string literal in the ERB.

Unrelated issue spotted

db/schema.rb is out of date versus db/migrate/ — 20260726060000_drop_persona_integration.rb is not reflected in it, so bundle exec rspec aborts with PendingMigrationError on a fresh checkout until you run RAILS_ENV=test bin/rails db:migrate. Left out of this PR to keep the diff focused.

Also left alone: app/views/slack/**/*.slocks still carries upstream Hack Club conduct links, conduct@hackclub.com, and :orpheus-*: emoji. Those are real links rather than examples and look like a separate porting job.

🤖 Generated with Claude Code

https://claude.ai/code/session_01X9XgkkN9VbgQH4ejEF2Ubj