feat(payment): add TokenPay payment plugin

Register a new TokenPay payment plugin with configurable API
credentials, payment URL generation, and signed callback
verification.

Also improve admin config fetching to support single-group
lookups and add backwards-compatible subscribe template loading
from legacy settings and bundled files when the database table
is unavailable.

app/Models/SubscribeTemplate.php

@@ -2,8 +2,16 @@
 
 namespace App\Models;
 
+use App\Protocols\Clash;
+use App\Protocols\ClashMeta;
+use App\Protocols\SingBox;
+use App\Protocols\Stash;
+use App\Protocols\Surfboard;
+use App\Protocols\Surge;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\QueryException;
 use Illuminate\Support\Facades\Cache;
+use Illuminate\Support\Facades\File;
 
 class SubscribeTemplate extends Model
 {
@@ -15,32 +23,131 @@ class SubscribeTemplate extends Model
     ];
 
     private static string $cachePrefix = 'subscribe_template:';
+    private static array $legacyTemplateFiles = [
+        'singbox' => [SingBox::CUSTOM_TEMPLATE_FILE, SingBox::DEFAULT_TEMPLATE_FILE],
+        'clash' => [Clash::CUSTOM_TEMPLATE_FILE, Clash::DEFAULT_TEMPLATE_FILE],
+        'clashmeta' => [
+            ClashMeta::CUSTOM_TEMPLATE_FILE,
+            ClashMeta::CUSTOM_CLASH_TEMPLATE_FILE,
+            ClashMeta::DEFAULT_TEMPLATE_FILE,
+        ],
+        'stash' => [
+            Stash::CUSTOM_TEMPLATE_FILE,
+            Stash::CUSTOM_CLASH_TEMPLATE_FILE,
+            Stash::DEFAULT_TEMPLATE_FILE,
+        ],
+        'surge' => [Surge::CUSTOM_TEMPLATE_FILE, Surge::DEFAULT_TEMPLATE_FILE],
+        'surfboard' => [Surfboard::CUSTOM_TEMPLATE_FILE, Surfboard::DEFAULT_TEMPLATE_FILE],
+    ];
 
     public static function getContent(string $name): ?string
     {
         $cacheKey = self::$cachePrefix . $name;
 
         return Cache::store('redis')->remember($cacheKey, 3600, function () use ($name) {
-            return self::where('name', $name)->value('content');
+            return self::resolveContent($name);
         });
     }
 
     public static function setContent(string $name, ?string $content): void
     {
-        self::updateOrCreate(
-            ['name' => $name],
-            ['content' => $content]
-        );
+        try {
+            self::updateOrCreate(
+                ['name' => $name],
+                ['content' => $content]
+            );
+        } catch (QueryException) {
+            admin_setting([self::legacySettingKey($name) => $content]);
+        }
         Cache::store('redis')->forget(self::$cachePrefix . $name);
     }
 
     public static function getAllContents(): array
     {
-        return self::pluck('content', 'name')->toArray();
+        try {
+            $contents = self::pluck('content', 'name')->toArray();
+            return $contents ?: self::getLegacyContents();
+        } catch (QueryException) {
+            return self::getLegacyContents();
+        }
     }
 
     public static function flushCache(string $name): void
     {
         Cache::store('redis')->forget(self::$cachePrefix . $name);
     }
+
+    /**
+     * Resolve template content with backwards-compatible fallbacks.
+     *
+     * @param string $name
+     * @return string|null
+     */
+    private static function resolveContent(string $name): ?string
+    {
+        try {
+            $template = self::query()
+                ->select('content')
+                ->where('name', $name)
+                ->first();
+
+            if ($template !== null) {
+                return $template->content;
+            }
+        } catch (QueryException) {
+            // Fall back to legacy sources when the new table is unavailable.
+        }
+
+        return self::getLegacyContent($name);
+    }
+
+    /**
+     * Collect all legacy template contents by protocol name.
+     *
+     * @return array<string, string>
+     */
+    private static function getLegacyContents(): array
+    {
+        $contents = [];
+
+        foreach (array_keys(self::$legacyTemplateFiles) as $name) {
+            $contents[$name] = self::getLegacyContent($name) ?? '';
+        }
+
+        return $contents;
+    }
+
+    /**
+     * Resolve template content from legacy settings and bundled files.
+     *
+     * @param string $name
+     * @return string|null
+     */
+    private static function getLegacyContent(string $name): ?string
+    {
+        $settingValue = admin_setting(self::legacySettingKey($name));
+        if ($settingValue !== null && $settingValue !== '') {
+            return $settingValue;
+        }
+
+        foreach (self::$legacyTemplateFiles[$name] ?? [] as $file) {
+            $path = base_path($file);
+            if (File::exists($path)) {
+                return File::get($path);
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * Build the legacy settings key for a template name.
+     *
+     * @param string $name
+     * @return string
+     */
+    private static function legacySettingKey(string $name): string
+    {
+        return "subscribe_template_{$name}";
+    }
 }