fix: review 修复——meta 覆盖、重复支付、卸载守卫、测试补全

- EditPost 保存时合并表单中的部分 meta 键，防止插件注入字段覆盖 unlocked_user_ids 等其他键（单篇解锁用户会失去权限的 bug）
- unlockPost：已有阅读权限（会员/作者/已解锁）直接跳文章，不重复支付
- subscribe：已有该套餐有效订阅直接跳我的订阅页
- uninstall：存在已启用的依赖者时拒绝卸载（与 disable 一致）
- .gitignore 排除 storage/media-library/temp 测试残留
- 测试：AdminPagesTest 补 /admin/plugins /admin/payments；新增 Livewire 保存验证 meta 保留、解锁/订阅防重复支付、卸载守卫

tests/Feature/MembershipFlowTest.php

@@ -112,7 +112,8 @@ class MembershipFlowTest extends TestCase
             'content_format' => 'markdown',
             'status' => 'published',
             'published_at' => now(),
-            'meta' => ['price' => 500],
+            // members_only：非会员被拦截，可单篇支付解锁
+            'meta' => ['price' => 500, 'members_only' => true],
         ]);
 
         $this->actingAs($this->user)
@@ -147,4 +148,40 @@ class MembershipFlowTest extends TestCase
         $this->assertSame('—', $payment->payable_label);
         $this->assertNull($payment->payable_url);
     }
+
+    public function test_unlock_post_skips_payment_when_already_unlocked(): void
+    {
+        $post = Post::create([
+            'title' => '已解锁',
+            'slug' => 'already-unlocked',
+            'content' => '内容',
+            'content_format' => 'markdown',
+            'status' => 'published',
+            'published_at' => now(),
+            'meta' => ['price' => 500, 'unlocked_user_ids' => [$this->user->id]],
+        ]);
+
+        $this->actingAs($this->user)
+            ->post('/posts/'.$post->id.'/unlock')
+            ->assertRedirect('/posts/already-unlocked.shtml');
+
+        $this->assertSame(0, Payment::query()->count());
+    }
+
+    public function test_subscribe_skips_payment_when_plan_already_active(): void
+    {
+        Subscription::create([
+            'user_id' => $this->user->id,
+            'membership_plan_id' => $this->plan->id,
+            'status' => 'active',
+            'starts_at' => now(),
+            'ends_at' => now()->addDays(30),
+        ]);
+
+        $this->actingAs($this->user)
+            ->post('/membership/'.$this->plan->id.'/subscribe')
+            ->assertRedirect(route('membership.mine'));
+
+        $this->assertSame(0, Payment::query()->count());
+    }
 }