feat: add captcha verification to contact form

Added math-based captcha system to prevent spam on the contact form:
- Created captcha API endpoint with simple arithmetic questions
- Added captcha UI component with refresh functionality
- Integrated captcha verification into contact form submission
- Relaxed spam filters since captcha provides better protection

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

messages/en.json

@@ -158,7 +158,7 @@
       "answers": {
         "accurate": "Yes, our AI is trained on verified theological sources and reviewed by seminary professors and pastors to ensure Biblical accuracy.",
         "free": "Core features including Bible reading, AI chat, and basic search are completely free. Premium features are available for advanced users.",
-        "languages": "We support 25+ languages including English, Spanish, Portuguese, French, German, and many more with native speaker quality.",
+        "languages": "We support 8 languages including English, Spanish, Portuguese, French, German, and many more with native speaker quality.",
         "offline": "Basic Bible reading is available offline. AI features and search require an internet connection for the best experience.",
         "privacy": "Your spiritual journey stays between you and God. We use industry-standard encryption and never share personal data.",
         "versions": "We offer multiple Bible versions including NIV, ESV, NASB, King James, and translations in many languages."