Fallback language defined

Severity: Recommended

When a translation is missing, the app needs to know what to show. Without a fallback, users see translation keys or blank content.

Check automatically:

# Check i18n config for fallback settings
grep -riE "fallback|defaultLocale|default.*lang|defaultLanguage" src/ --include="*.ts" --include="*.js" --include="*.json" 2>/dev/null | grep -v node_modules | head -10

# Check next.config.js for Next.js i18n
grep -A5 "i18n" next.config.* 2>/dev/null

# Check i18next config specifically
grep -riE "fallbackLng|fallbackLanguage" . --include="*.ts" --include="*.js" --include="*.json" 2>/dev/null | grep -v node_modules

Pass criteria:

• Fallback language explicitly configured (usually English)
• Fallback chain defined if multiple fallbacks (e.g., es-MX → es → en)
• Tested: missing translation shows fallback, not key

Fail criteria:

• No fallback configured (shows raw keys)
• Fallback to empty string (blank UI)
• Assumed but not explicit in config

Evidence to capture:

• Fallback language configured
• Fallback chain (if any)
• Config location

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