docs: update documentation to reflect changes from TON to GRAM, including method renaming and new top-up method

docs/getting-started/configuration.md

@@ -8,19 +8,21 @@ FragmentClient(
     api_key: str,
     cookies: dict[str, Any] | str,
     wallet_version: str = "V5R1",
+    api_provider: str = "tonapi",
     timeout: float = 30.0,
 )
 ```
 
 ## Parameters
 
-- `seed`: wallet mnemonic (**12, 18, or 24 words**)
-- `api_key`: Tonapi key from https://tonconsole.com
+- `seed`: wallet mnemonic (**12 or 24 words**)
+- `api_key`: API key — from [tonconsole.com](https://tonconsole.com) (tonapi) or [@toncenter](https://t.me/toncenter)
 - `cookies`: Fragment cookies as a dictionary or JSON string
-- `wallet_version`: `"V4R2"` or `"V5R1"`
+- `wallet_version`: `"V4R2"`, `"V5R1"`, `"HighloadV2"`, or `"HighloadV3R1"`
+- `api_provider`: blockchain API provider — `"tonapi"` (default) or `"toncenter"`
 - `timeout`: request timeout in seconds
 
-**If `api_key` is too short or cookies are incomplete, initialization fails immediately.**
+**If `api_key` or cookies are missing, initialization fails immediately.**
 
 ## Required cookies
 
@@ -34,26 +36,34 @@ FragmentClient(
 ```python
 from pyfragment import FragmentClient
 
-client = FragmentClient(
+async with FragmentClient(
     seed="word1 word2 ... word24",
-    api_key="YOUR_TONAPI_KEY",
+    api_key="YOUR_API_KEY",
     cookies={
         "stel_ssid": "...",
         "stel_dt": "...",
         "stel_token": "...",
         "stel_ton_token": "...",
     },
-)
-```
-
-Use it inside async context manager:
-
-```python
-async with client:
+) as client:
     wallet = await client.get_wallet()
 ```
 
-You can also create the client directly inside `async with` if you prefer one-block setup.
+## Switching API provider
+
+By default, the library uses [tonconsole.com](https://tonconsole.com) (tonapi). To use [toncenter](https://t.me/toncenter) instead, pass `api_provider="toncenter"`:
+
+```python
+async with FragmentClient(
+    seed="...",
+    api_key="YOUR_TONCENTER_API_KEY",
+    cookies={...},
+    api_provider="toncenter",
+) as client:
+    ...
+```
+
+Both providers work identically — the correct `tonutils` client is selected automatically based on `api_provider`.
 
 ## Validation behavior
 
@@ -62,8 +72,7 @@ At initialization, library validates:
 - seed format,
 - cookie shape and required keys,
 - supported wallet version,
+- supported API provider,
 - parseability of cookie JSON strings.
 
 Constructor-level issues are raised as `ConfigurationError` or `CookieError`.
-
-**Tip:** keep validation failures visible in logs during initial integration. They save a lot of debugging time.

docs/getting-started/credentials-and-cookies.md

@@ -8,7 +8,7 @@ Generate an API key at https://tonconsole.com.
 
 ## Seed phrase
 
-Use your TON wallet mnemonic.
+Use your GRAM (ex TON) wallet mnemonic.
 
 - **Keep it private.**
 - **Never log it or commit it to git.**

docs/getting-started/quickstart.md

@@ -6,21 +6,33 @@ Use this minimal example to verify that your credentials, cookies, and wallet se
 import asyncio
 
 from pyfragment import FragmentClient
+from pyfragment.enums import PaymentMethod
 
 
 async def main() -> None:
     async with FragmentClient(
         seed="word1 word2 ... word24",
-        api_key="YOUR_TONAPI_KEY",
+        api_key="YOUR_API_KEY",  # tonconsole.com (tonapi, default) or t.me/toncenter
         cookies={
             "stel_ssid": "...",
             "stel_dt": "...",
             "stel_token": "...",
             "stel_ton_token": "...",
         },
+        wallet_version="V5R1",   # or "V4R2", "HighloadV2", "HighloadV3R1"
+        api_provider="tonapi",   # or "toncenter"
     ) as client:
         wallet = await client.get_wallet()
-        print(wallet)
+        print(f"GRAM: {wallet.gram_balance} | USDT: {wallet.usdt_balance}")
+
+        recipient = "https://t.me/username"  # also: @username, username
+
+        stars = await client.purchase_stars(recipient, amount=500, payment_method=PaymentMethod.USDT_GRAM)
+        print(f"Sent {stars.amount} Stars to {stars.username} | tx: {stars.transaction_id}")
+
+        premium = await client.purchase_premium(recipient, months=6, payment_method=PaymentMethod.GRAM)
+        print(f"Sent Premium {premium.amount}m to {premium.username} | tx: {premium.transaction_id}")
+
 
 asyncio.run(main())
 ```