feat: Implement payment notification system and API structure

- Added notifications for successful payments in `api/core/notifications.py`.
- Created main API entry point in `api/main.py` with FastAPI integration.
- Established routing structure in `api/routes/__init__.py` and `api/routes/pally.py` for handling payment callbacks.
- Developed billing handlers in `bot/handlers/billing.py` and `bot/handlers/buy.py` for subscription management.
- Introduced state management for user interactions in `bot/states/`.
- Created user interface elements in `bot/keyboards/` for navigation and payment processing.
- Set up middleware for dependency injection in `bot/middlewares/di.py`.
- Added support for user commands and interactions in `bot/handlers/common.py` and `bot/handlers/support.py`.
- Implemented logging and error handling throughout the bot's functionality.
- Created entry point script for API server in `entrypoints/api.sh`.

bot/keyboards/client.py

@@ -0,0 +1,125 @@
+from aiogram.types import InlineKeyboardButton, InlineKeyboardMarkup
+from aiogram.utils.keyboard import InlineKeyboardBuilder
+
+from config import settings
+from misc.utils import convert_duration_to_int
+from schemas.subscriptions import SubscriptionDuration
+
+main_menu = InlineKeyboardBuilder(
+    [
+        [InlineKeyboardButton(text="📊 Подписка", callback_data="sub_info")],
+        [
+            InlineKeyboardButton(text="⚙️ Купить", callback_data="buy"),
+            InlineKeyboardButton(text="⁉️ FAQ", callback_data="faq"),
+        ],
+        [
+            InlineKeyboardButton(text="📢 Наш Канал", url="https://t.me/maleniavpn"),
+            InlineKeyboardButton(text="🎧 Тех. Поддержка", url="https://t.me/maleniasupportbot"),
+        ],
+        [InlineKeyboardButton(text="🔗 Обновить ссылку", callback_data="update_link")],
+        [InlineKeyboardButton(text="👤 Реферальная система", callback_data="referal")],
+    ]
+).as_markup()
+
+_return_to_menu_btn: InlineKeyboardButton = InlineKeyboardButton(
+    text="⬅️ Назад", callback_data="menu:main"
+)
+
+return_to_menu: InlineKeyboardMarkup = InlineKeyboardBuilder([[_return_to_menu_btn]]).as_markup()
+
+payment_gateways: InlineKeyboardMarkup = InlineKeyboardBuilder(
+    [
+        [InlineKeyboardButton(text="💸 Pally (СБП / Карта)", callback_data="billing:pally")],
+        [InlineKeyboardButton(text="✍️ Перейти в поддержку", url="https://t.me/maleniasupportbot")],
+        [_return_to_menu_btn],
+    ]
+).as_markup()
+
+close_kb: InlineKeyboardMarkup = InlineKeyboardBuilder(
+    [[InlineKeyboardButton(text="❌", callback_data="delete")]]
+).as_markup()
+
+support_url_kb: InlineKeyboardMarkup = InlineKeyboardBuilder(
+    [
+        [InlineKeyboardButton(text="✍️ Перейти в поддержку", url="https://t.me/maleniasupportbot")],
+        [_return_to_menu_btn],
+    ]
+).as_markup()
+
+
+def _return_btn(data: str = "menu:main", text: str = "⬅️ Назад") -> InlineKeyboardButton:
+    return InlineKeyboardButton(text=text, callback_data=data)
+
+
+def build_return_menu(data: str = "menu:main", text: str = "⬅️ Назад") -> InlineKeyboardMarkup:
+    return InlineKeyboardBuilder([[_return_btn(data, text)]]).as_markup()
+
+
+def devices_selector(current: int = settings.min_devices, whitelists: bool = False):
+    builder = InlineKeyboardBuilder()
+
+    buttons = [
+        InlineKeyboardButton(
+            text=f"{'✅ ' if i == current else ''}{i}", callback_data=f"devices:{i}"
+        )
+        for i in range(settings.min_devices, settings.max_devices + 1)
+    ]
+    builder.add(*buttons).adjust(6)
+
+    wl_icon = "✅ " if whitelists else ""
+    builder.row(
+        InlineKeyboardButton(
+            text=f"{wl_icon}Обход Белых Списков (+100₽)",
+            callback_data="whitelist:toggle",
+        )
+    )
+    builder.row(InlineKeyboardButton(text="🟢", callback_data="confirm"))
+    builder.row(_return_to_menu_btn)
+
+    return builder.as_markup()
+
+
+def duration_selector(
+    current: SubscriptionDuration = SubscriptionDuration.MONTH,
+    back_cb: str = "menu:main",
+) -> InlineKeyboardMarkup:
+    builder = InlineKeyboardBuilder()
+    duration_int = convert_duration_to_int(current)
+
+    durations = [
+        (1, "1 Месяц"),
+        (3, "3 Месяца"),
+        (6, "6 Месяцев"),
+        (12, "1 Год"),
+    ]
+
+    for val, label in durations:
+        is_selected = val == duration_int
+
+        builder.button(
+            text=f"{'✅ ' if is_selected else ''}{label}",
+            callback_data=f"duration:{val}",
+        )
+
+    builder.row(InlineKeyboardButton(text="🛒 Перейти к оплате", callback_data="confirm"))
+    builder.row(_return_btn(back_cb))
+
+    return builder.as_markup()
+
+
+def referals_kb(share_link: str) -> InlineKeyboardMarkup:
+    return InlineKeyboardBuilder(
+        [
+            [InlineKeyboardButton(text="🔗 Поделиться ссылкой", url=share_link)],
+            [_return_to_menu_btn],
+        ]
+    ).as_markup()
+
+
+def pay_url(url: str) -> InlineKeyboardMarkup:
+    return InlineKeyboardBuilder(
+        [
+            [InlineKeyboardButton(text="💸 Оплатить", url=url)],
+            [InlineKeyboardButton(text="❌", callback_data="menu:main")],
+        ]
+    ).as_markup()