feat: convert ssh tunnels into a plugin

src/backend/database/db/schema.mysql.ts

@@ -466,23 +466,6 @@ export const sshCredentialUsage = mysqlTable(
   ],
 );
 
-export const c2sTunnelPresets = mysqlTable("c2s_tunnel_presets", {
-  id: int("id").autoincrement().primaryKey(),
-  userId: varchar("user_id", { length: 255 })
-    .notNull()
-    .references(() => users.id, { onDelete: "cascade" }),
-  name: varchar("name", { length: 255 }).notNull(),
-  config: text("config").notNull(),
-  platform: text("platform"),
-  computerName: text("computer_name"),
-  createdAt: varchar("created_at", { length: 255 })
-    .notNull()
-    .default(sql`(CURRENT_TIMESTAMP)`),
-  updatedAt: varchar("updated_at", { length: 255 })
-    .notNull()
-    .default(sql`(CURRENT_TIMESTAMP)`),
-});
-
 export const sshFolders = mysqlTable(
   "ssh_folders",
   {