Name the app by its display name in mails and pages; drop placeholder store links and the template logo

[dadachi]

Summary

One PR for both issues: #162's fix uses the display_name setting that #161 adds. Two commits, one per issue.

#161: mails

• New top-level display_name: Native App Template in config/settings.yml. The rename's humanized-title pattern turns it into the generated app's name (NativeAppTemplate→OrangeBaton gives Orange Baton; I checked this by running rename.rb on a copy). site.name / business.name stay as the one-word identifier-like names.
• Mails use it for the sender name (email.default_from_with_name, also support_with_name), the invitation text ("Open Native App Template", "モバイルアプリNative App Templateで…"), a deleted inviter's name and the footer (copyright line and site link, HTML and text).
• Store links: rule: blank means left out. mobile_app.app_store_url / play_store_url are now "" by default instead of the idxxxxxxxxxx / com.yourdomain… placeholders. Shopkeeper::NotificationMailer#store_links keeps only the URLs that are set, so the mail shows neither, one or both. Link labels moved to locale keys (%{mobile_app} for iOS / %{mobile_app} iOS版). I chose blank over a placeholder? check because it can't miss a placeholder spelled differently, and the generated app is in the same state.
• mobile_app.name, name_ios and name_android are removed (nothing uses them now).

#162: password-reset page logo

• shopkeeper_auth/reset_passwords/edit shows display_name as a text wordmark instead of <img src="/icon.svg">.
• Why text and not a configurable logo: it follows the rename, so a generated app is correct out of the box with no asset to remember. A logo setting would still need someone to supply the asset, and until then it would show the template's "N" (or nothing). An app that wants a logo can add one to the view.
• The minimal and errors layouts' <title> use display_name too.
• README's new "App name and store links" section explains both names and the store-link rule. It also lists the public/ icons (favicon, icon.svg, icon*.png, apple-touch-icon.png) as the template's, to replace. These are still used as favicons.

Rename safety: the new strings have no article before a renameable word or the product name.

Tests

• notification_mailer_test (en and ja): invitation names the display name and not the identifier name; no store links while blank; each set link shown (HTML and text); footer uses the display name; From display name is the display name; deleted-inviter fallback uses the display name. The identifier-name check is skipped when the two names are the same, e.g. a one-word product name after the rename.
• reset_passwords_controller_test: the page has no <img> and names the app in text and <title>.
• errors_controller_test: HTML error page title uses the display name.

I reverted the app changes and confirmed the new tests fail on the old code.

Local results: bin/rails test (654 runs, 0 failures), bin/rubocop, erb_lint --lint-all, brakeman and bundler-audit all pass.

Closes #161
Closes #162

🤖 Generated with Claude Code

https://claude.ai/code/session_01UZJxUoubntzu7Ec7DPVfAr