Add manual chain export/import RPC endpoints and fix chain_id in wallet adapter

- Add /export-chain endpoint to export full blockchain state (blocks, accounts, transactions) as JSON
- Add /import-chain endpoint to import chain state with backup and data clearing
- Add /force-sync endpoint to trigger reorg by fetching and importing peer's chain state
- Fix duplicate import_block implementation (remove redundant async with _import_lock block)
- Fix wallet adapter to use chain_id=ait-testnet instead of ait

cli/utils/dual_mode_wallet_adapter.py

@@ -311,7 +311,7 @@ class DualModeWalletAdapter:
             
         rpc_url = self.config.blockchain_rpc_url
         try:
-            resp = httpx.get(f"{rpc_url}/rpc/getBalance/{from_address}?chain_id=ait-mainnet", timeout=5)
+            resp = httpx.get(f"{rpc_url}/rpc/account/{from_address}?chain_id=ait-testnet", timeout=5)
             if resp.status_code == 200:
                 data = resp.json()
                 chain_balance = data.get("balance", 0)