Add i18n support to profile page

[Copilot]

The profile page had all UI strings hardcoded in English with no translation support, unlike the main page which already used i18next.

Changes

Bug fix — localization.js

applyLocalization() was concatenating translations onto existing innerText instead of replacing it, causing doubled text on language switches:

// Before (broken on language change)
element.innerText = i18next.t(element.getAttribute('i18n')) + element.innerText;

// After
element.innerText = i18next.t(element.getAttribute('i18n'));

Translation keys — en.json / de.json

• Added 81 profile-specific keys (profile_*) for all UI strings: navigation, section headings, buttons, input placeholders, status labels, empty states, and dynamic content
• Added complete German translations for all new keys

profile/index.html

• Added i18n attributes to all static text elements; cleared hardcoded text content
• Added i18n-placeholder attributes to all inputs
• Used <span i18n="..."> wrapper for "Back" text (SVG sibling prevents direct innerText replacement on parent <a>)
• Removed i18n from the 2FA toggle button since its text is state-driven in JS

profile.js / settings/device.js

• Imported and call applyLocalization(item) on dynamically cloned SSO template nodes
• Replaced all hardcoded strings in dynamically created DOM nodes with i18next.t('profile_*') — passkeys, API keys, devices, trusted apps, SSO entries, 2FA status, and the double-click confirm button

Original prompt

Add translations to the profile page

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