fix: resolve all TypeScript build errors

- Remove unused imports (LoginModal, Zap) and variables
- Fix Language type mismatches across components
- Update HeaderBar interface to use Language type
- Remove unused onLoginClick parameter
- Fix duplicate translation keys by renaming auth steps
- Remove invalid language prop from CommunitySection

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

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

web/src/i18n/translations.ts

@@ -301,12 +301,12 @@ export const translations = {
     scanQRCodeInstructions: 'Scan this QR code with Google Authenticator or Authy',
     otpSecret: 'Or enter this secret manually:',
     qrCodeHint: 'QR code (if scanning fails, use the secret below):',
-    step1Title: 'Step 1: Install Google Authenticator',
-    step1Desc: 'Download and install Google Authenticator from your app store',
-    step2Title: 'Step 2: Add account',
-    step2Desc: 'Tap "+", then choose "Scan QR code" or "Enter a setup key"',
-    step3Title: 'Step 3: Verify setup',
-    step3Desc: 'After setup, continue to enter the 6-digit code',
+    authStep1Title: 'Step 1: Install Google Authenticator',
+    authStep1Desc: 'Download and install Google Authenticator from your app store',
+    authStep2Title: 'Step 2: Add account',
+    authStep2Desc: 'Tap "+", then choose "Scan QR code" or "Enter a setup key"',
+    authStep3Title: 'Step 3: Verify setup',
+    authStep3Desc: 'After setup, continue to enter the 6-digit code',
     setupCompleteContinue: 'I have completed setup, continue',
     copy: 'Copy',
     completeRegistration: 'Complete Registration',
@@ -713,12 +713,12 @@ export const translations = {
     scanQRCodeInstructions: '使用Google Authenticator或Authy扫描此二维码',
     otpSecret: '或手动输入此密钥：',
     qrCodeHint: '二维码（如果无法扫描，请使用下方密钥）：',
-    step1Title: '步骤1：下载Google Authenticator',
-    step1Desc: '在手机应用商店下载并安装Google Authenticator应用',
-    step2Title: '步骤2：添加账户',
-    step2Desc: '在应用中点击“+”，选择“扫描二维码”或“手动输入密钥”',
-    step3Title: '步骤3：验证设置',
-    step3Desc: '设置完成后，点击下方按钮输入6位验证码',
+    authStep1Title: '步骤1：下载Google Authenticator',
+    authStep1Desc: '在手机应用商店下载并安装Google Authenticator应用',
+    authStep2Title: '步骤2：添加账户',
+    authStep2Desc: '在应用中点击“+”，选择“扫描二维码”或“手动输入密钥”',
+    authStep3Title: '步骤3：验证设置',
+    authStep3Desc: '设置完成后，点击下方按钮输入6位验证码',
     setupCompleteContinue: '我已完成设置，继续',
     copy: '复制',
     completeRegistration: '完成注册',