test: remove tests that do not test behavior and strengthen weak ones

- Remove tests that only check markup, CSS, static text, wire:key strings,
  framework behavior, copied app logic, or expect(true)
- Replace source-grep and Reflection checks of security fixes with tests
  that run the real code (shell quoting, locked properties, 403 checks,
  webhook fork trust, log redaction, Sentinel token cleanup)
- Assert response bodies and unchanged data on API error paths
- Run the Traefik version job through handle() instead of private methods
- Update stale tests for scheduled task props, the default Postgres image,
  and the disabled transfer link of unvalidated servers

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/Unit/HealthCheckCommandInjectionTest.php

@@ -309,32 +309,6 @@ it('uses sanitized method in full_healthcheck_url display', function () {
         ->and($result)->not->toContain('evil');
 });
 
-it('validates healthCheckCommand rejects strings over 1000 characters', function () {
-    $rules = [
-        'healthCheckCommand' => 'nullable|string|max:1000',
-    ];
-
-    $validator = Validator::make(
-        ['healthCheckCommand' => str_repeat('a', 1001)],
-        $rules
-    );
-
-    expect($validator->fails())->toBeTrue();
-});
-
-it('validates healthCheckCommand accepts strings under 1000 characters', function () {
-    $rules = [
-        'healthCheckCommand' => 'nullable|string|max:1000',
-    ];
-
-    $validator = Validator::make(
-        ['healthCheckCommand' => 'pg_isready -U postgres'],
-        $rules
-    );
-
-    expect($validator->fails())->toBeFalse();
-});
-
 /**
  * Helper: Invokes the private generate_healthcheck_commands() method via reflection.
  */