Enhance verification system with multi-provider support and alt-account detection

- Added support for multiple captcha providers including Google reCAPTCHA (v2 and v3), hCaptcha, and Cloudflare Turnstile.
- Introduced new fields in the verification configuration for selecting captcha providers and enabling alt-account detection.
- Implemented logic to handle verification attempts and flag potential alt accounts based on IP and invite code analysis.
- Updated environment configuration to include necessary keys for captcha providers.
- Enhanced the user interface to allow selection of captcha providers in the verification setup.
- Improved backend handling of verification records to store additional data related to captcha provider usage.

apps/webui/src/messages/en.json

@@ -477,6 +477,15 @@
         "BUTTON": "Button",
         "CAPTCHA": "Captcha (WebUI)"
       },
+      "captchaProvider": "Captcha provider",
+      "captchaProviderHint": "Providers without .env keys are hidden. Google keys: RECAPTCHA_SITE_KEY / RECAPTCHA_SECRET_KEY.",
+      "captchaProviders": {
+        "MATH": "Math challenge",
+        "RECAPTCHA_V2": "Google reCAPTCHA v2",
+        "RECAPTCHA_V3": "Google reCAPTCHA v3",
+        "HCAPTCHA": "hCaptcha",
+        "TURNSTILE": "Cloudflare Turnstile"
+      },
       "failAction": "Action on failure",
       "failActions": {
         "KICK": "Kick",
@@ -486,7 +495,15 @@
       "channelId": "Verification channel",
       "verifiedRoleId": "Role after verification",
       "unverifiedRoleId": "Role before verification",
-      "minAccountAgeDays": "Minimum account age (days)"
+      "minAccountAgeDays": "Minimum account age (days)",
+      "altTitle": "Alt-account detection",
+      "altDescription": "Flags likely alternate accounts via shared captcha IP (salted hash) and invite clustering. No browser fingerprinting.",
+      "altDetectionEnabled": "Enable alt detection",
+      "altBlockOnMatch": "Block on match",
+      "altBlockOnMatchHint": "Uses the configured fail action (Kick/Ban/None). Off = flag only, still verify.",
+      "altIpWindowDays": "IP window (days)",
+      "altInviteWindowHours": "Invite cluster window (hours)",
+      "altMaxAccountsPerInvite": "Max accounts per invite (cluster)"
     },
     "leveling": {
       "title": "Leveling & XP",