Region-aware pricing: GeoIP + VPN-детект + публичный /plans + бот

- modules::geoip — DB-IP Lite (.mmdb, без регистрации/ключа, в отличие от
  MaxMind) для страны по IP, X4BNet lists_vpn для грубой VPN/датацентр-
  эвристики. Обе базы скачиваются в рантайме, обновление — фоновая
  задача в tasks.rs (раз в сутки по умолчанию, GEOIP_REFRESH_INTERVAL).
- GET /api/v1/billing/plans (public_router, без auth_guard) — цены в
  валюте, определённой по IP посетителя (X-Real-IP/X-Forwarded-For,
  см. nginx-конфиги). VPN/датацентр IP -> всегда базовый USD, чтобы
  обход региона через любой публичный VPN не обесценивал скидки.
- Бот: Bot API не отдаёт IP пользователя вообще — валюта определяется по
  Telegram language_code. Показ цены — в валюте региона, САМА оплата
  через CryptoBot остаётся в USD/USDT (провайдер биллит 1:1 к USD-цене
  тарифа, менять валюту списания нельзя, не меняя сам провайдер).

Cargo.lock

@@ -2,6 +2,12 @@
 # It is not intended for manual editing.
 version = 4
 
+[[package]]
+name = "adler2"
+version = "2.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "320119579fcad9c21884f5c4861d16174d0e06250625266f50fe6898340abefa"
+
 [[package]]
 name = "ahash"
 version = "0.7.8"
@@ -649,6 +655,15 @@ version = "2.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "19d374276b40fb8bbdee95aef7c7fa6b5316ec764510eb64b8dd0e2ed0d7e7f5"
 
+[[package]]
+name = "crc32fast"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9481c1c90cbf2ac953f07c8d4a58aa3945c425b7185c9154d67a65e4230da511"
+dependencies = [
+ "cfg-if",
+]
+
 [[package]]
 name = "crossbeam-epoch"
 version = "0.9.18"
@@ -1056,6 +1071,16 @@ version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5baebc0774151f905a1a2cc41989300b1e6fbb29aff0ceffa1064fdd3088d582"
 
+[[package]]
+name = "flate2"
+version = "1.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "843fba2746e448b37e26a819579957415c8cef339bf08564fe8b7ddbd959573c"
+dependencies = [
+ "crc32fast",
+ "miniz_oxide",
+]
+
 [[package]]
 name = "flume"
 version = "0.11.1"
@@ -1856,6 +1881,15 @@ version = "2.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d98f6fed1fde3f8c21bc40a1abb88dd75e67924f9cffc3ef95607bad8017f8e2"
 
+[[package]]
+name = "ipnetwork"
+version = "0.20.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bf466541e9d546596ee94f9f69590f89473455f88372423e0008fc1a7daf100e"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "iri-string"
 version = "0.7.12"
@@ -2055,6 +2089,18 @@ version = "0.8.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "47e1ffaa40ddd1f3ed91f717a33c8c0ee23fff369e3aa8772b9605cc1d22f4c3"
 
+[[package]]
+name = "maxminddb"
+version = "0.24.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d6087e5d8ea14861bb7c7f573afbc7be3798d3ef0fae87ec4fd9a4de9a127c3c"
+dependencies = [
+ "ipnetwork",
+ "log",
+ "memchr",
+ "serde",
+]
+
 [[package]]
 name = "md-5"
 version = "0.10.6"
@@ -2135,6 +2181,16 @@ dependencies = [
  "unicase",
 ]
 
+[[package]]
+name = "miniz_oxide"
+version = "0.8.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1fa76a2c86f704bdb222d66965fb3d63269ce38518b83cb0575fca855ebb6316"
+dependencies = [
+ "adler2",
+ "simd-adler32",
+]
+
 [[package]]
 name = "mio"
 version = "1.2.0"
@@ -2173,9 +2229,12 @@ dependencies = [
  "chrono",
  "clap",
  "dotenvy",
+ "flate2",
  "hex",
  "hmac 0.13.0",
+ "ipnet",
  "jsonwebtoken",
+ "maxminddb",
  "metrics",
  "metrics-exporter-prometheus",
  "rand 0.8.6",
@@ -3451,6 +3510,12 @@ dependencies = [
  "rand_core 0.6.4",
 ]
 
+[[package]]
+name = "simd-adler32"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "703d5c7ef118737c72f1af64ad2f6f8c5e1921f818cdcb97b8fe6fc69bf66214"
+
 [[package]]
 name = "simdutf8"
 version = "0.1.5"