Fix contract detail balance display

[YoshiyukiSakura]

Summary

• Fix contract detail balance lookup by allowing /api/plugin/evm/accounts to include contracts when explicitly requested.
• For single contract balance display, read contract-native balance and AA/paymaster getDeposit() balance when supported, so deposited HEI does not render as 0 HEI.
• Update cursor typings and API docs for the new include_contracts parameter.

Fixes #48

Verification

• go test ./plugins/evm/http
• npm run build

Notes

• Full go test ./plugins/evm/dao is blocked locally by the existing dao_test init path requiring ../../../configs/config.yaml plus MySQL/Redis.

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