Add Gravatar and DNS Records collectors

Two pure-PHP collectors, no Python/venv/subprocess needed:
- GravatarRunner (email): checks gravatar.com/avatar/{md5}?d=404 for a
  200 vs 404. Scoped to that binary signal since Gravatar's profile
  JSON endpoint now requires API auth even for real, public profiles
  (confirmed against Gravatar's own creator's email).
- DnsRunner (domain): dns_get_record() for A/AAAA/MX/NS/TXT/CNAME. Raw
  payload is naturally keyed by record type, which the existing
  generic list-renderer on the investigation page turns into one
  collapsible section per type with no UI changes needed.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

tests/Unit/Osint/DnsRunnerTest.php

@@ -0,0 +1,54 @@
+<?php
+
+namespace Tests\Unit\Osint;
+
+use App\Models\Target;
+use App\Osint\Runners\DnsRunner;
+use App\Osint\RunnerException;
+use Tests\TestCase;
+
+class DnsRunnerTest extends TestCase
+{
+    public function test_rejects_non_domain_targets(): void
+    {
+        $target = new Target(['type' => 'ip', 'value' => '8.8.8.8']);
+
+        $this->expectException(RunnerException::class);
+
+        (new DnsRunner)->run($target);
+    }
+
+    public function test_rejects_unsafe_domain_format(): void
+    {
+        $target = new Target(['type' => 'domain', 'value' => '../../etc/passwd']);
+
+        $this->expectException(RunnerException::class);
+
+        (new DnsRunner)->run($target);
+    }
+
+    /**
+     * example.com is IANA-controlled and has had stable NS/A records for
+     * decades — safe to rely on for a real (non-mocked) DNS lookup.
+     */
+    public function test_resolves_a_real_stable_domain(): void
+    {
+        $target = new Target(['type' => 'domain', 'value' => 'example.com']);
+
+        $result = (new DnsRunner)->run($target);
+
+        $this->assertArrayHasKey('NS', $result->raw);
+        $this->assertNotEmpty($result->raw['NS']);
+        $this->assertStringContainsString('DNS record', $result->summary);
+    }
+
+    public function test_reports_no_records_for_a_nonexistent_domain(): void
+    {
+        $target = new Target(['type' => 'domain', 'value' => 'this-domain-should-not-exist-osint-test.invalid']);
+
+        $result = (new DnsRunner)->run($target);
+
+        $this->assertSame([], $result->raw);
+        $this->assertSame('No DNS records found.', $result->summary);
+    }
+}

tests/Unit/Osint/GravatarRunnerTest.php

@@ -0,0 +1,67 @@
+<?php
+
+namespace Tests\Unit\Osint;
+
+use App\Models\Target;
+use App\Osint\Runners\GravatarRunner;
+use App\Osint\RunnerException;
+use Illuminate\Support\Facades\Http;
+use Tests\TestCase;
+
+class GravatarRunnerTest extends TestCase
+{
+    public function test_reports_avatar_found(): void
+    {
+        Http::fake(['gravatar.com/avatar/*' => Http::response('', 200)]);
+
+        $target = new Target(['type' => 'email', 'value' => 'test@example.com']);
+
+        $result = (new GravatarRunner)->run($target);
+
+        $this->assertTrue($result->raw['has_avatar']);
+        $this->assertNotNull($result->raw['avatar_url']);
+        $this->assertStringContainsString('Gravatar image found', $result->summary);
+    }
+
+    public function test_reports_no_avatar(): void
+    {
+        Http::fake(['gravatar.com/avatar/*' => Http::response('', 404)]);
+
+        $target = new Target(['type' => 'email', 'value' => 'test@example.com']);
+
+        $result = (new GravatarRunner)->run($target);
+
+        $this->assertFalse($result->raw['has_avatar']);
+        $this->assertNull($result->raw['avatar_url']);
+        $this->assertSame('No Gravatar found for this email.', $result->summary);
+    }
+
+    public function test_rejects_non_email_targets(): void
+    {
+        $target = new Target(['type' => 'domain', 'value' => 'example.com']);
+
+        $this->expectException(RunnerException::class);
+
+        (new GravatarRunner)->run($target);
+    }
+
+    public function test_rejects_invalid_email_format(): void
+    {
+        $target = new Target(['type' => 'email', 'value' => 'not-an-email']);
+
+        $this->expectException(RunnerException::class);
+
+        (new GravatarRunner)->run($target);
+    }
+
+    public function test_throws_on_unexpected_status(): void
+    {
+        Http::fake(['gravatar.com/avatar/*' => Http::response('', 500)]);
+
+        $target = new Target(['type' => 'email', 'value' => 'test@example.com']);
+
+        $this->expectException(RunnerException::class);
+
+        (new GravatarRunner)->run($target);
+    }
+}