feat: add captcha-backed forum security hardening

tests/Unit/BotRiskScorerTest.php

@@ -0,0 +1,52 @@
+<?php
+
+use cPad\Plugins\Forum\Services\Security\BotRiskScorer;
+
+uses(Tests\TestCase::class);
+
+it('maps bot risk thresholds to the expected decisions', function () {
+    config()->set('forum_bot_protection.thresholds', [
+        'allow' => 20,
+        'log' => 20,
+        'captcha' => 40,
+        'moderate' => 60,
+        'block' => 80,
+    ]);
+
+    $scorer = app(BotRiskScorer::class);
+
+    expect($scorer->score(['behavior' => 10]))->toMatchArray([
+        'risk_score' => 10,
+        'decision' => 'allow',
+        'requires_review' => false,
+        'blocked' => false,
+    ]);
+
+    expect($scorer->score(['behavior' => 20]))->toMatchArray([
+        'risk_score' => 20,
+        'decision' => 'log',
+        'requires_review' => false,
+        'blocked' => false,
+    ]);
+
+    expect($scorer->score(['behavior' => 40]))->toMatchArray([
+        'risk_score' => 40,
+        'decision' => 'captcha',
+        'requires_review' => false,
+        'blocked' => false,
+    ]);
+
+    expect($scorer->score(['behavior' => 60]))->toMatchArray([
+        'risk_score' => 60,
+        'decision' => 'moderate',
+        'requires_review' => true,
+        'blocked' => false,
+    ]);
+
+    expect($scorer->score(['behavior' => 80]))->toMatchArray([
+        'risk_score' => 80,
+        'decision' => 'block',
+        'requires_review' => false,
+        'blocked' => true,
+    ]);
+});