Add Holehe collector for email targets

Closes the email target-type gap (previously had zero collectors).
Checks whether an email is registered on 120+ sites via the
password-reset-oracle technique. Shares the Sherlock/whois venv.

HoleheRunner gates success on the CSV file existing rather than the
process exit code: holehe's CLI calls Python's exit("message") right
after writing results on its normal success path, which always yields
exit code 1 regardless of outcome — discovered while verifying this
end-to-end against the real dev server and queue worker.

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

app/Osint/RunnerRegistry.php

@@ -3,6 +3,7 @@
 namespace App\Osint;
 
 use App\Osint\Runners\CrtShRunner;
+use App\Osint\Runners\HoleheRunner;
 use App\Osint\Runners\IpApiRunner;
 use App\Osint\Runners\SherlockRunner;
 use App\Osint\Runners\TheHarvesterRunner;
@@ -23,6 +24,7 @@ class RunnerRegistry
         'whois' => WhoisRunner::class,
         'ip-api' => IpApiRunner::class,
         'theharvester' => TheHarvesterRunner::class,
+        'holehe' => HoleheRunner::class,
     ];
 
     public function has(string $sourceKey): bool