client/container: ethereum-based: support Etherscan V2, add more L2 chains

- Implements support for unified API via Etherscan V2 (ethereum-based)
  * All ethereum-based L2s are now accessed via single API endpoint
    - Chains are now available via chain ID
  * Updates API key requirement for `fetch` ethereum-based subaccounts
    - The API key's value must now be prepended with "etherscan"
      * Previously was prepended per-chain ("ethereum" or "polygon")
    - The API key is now *required* (can be generated at etherscan.io)
      * Resolves fatal error in Etherscan::parse_response()
      * Impl will now handle if:
        - Config's API key/value is malformed
        - Etherscan API key was not given
        - Etherscan response is fatal

- Adds support for more L2s
  * Arbitrum (One)
  * Optimism
  * Base

- Adds more L2s to existing accounts
  * Coinbase Wallet
  * Ledger Live
  * MetaMask

- Updates documentation
  * Update default generated `fetch` config
  * Update `fetch` usage help
  * Update README

container/src/hledger-flow/accounts/ledger/template/ledger/arbitrum/ledger-arbitrum.rules

@@ -0,0 +1,20 @@
+# docker-finance | modern accounting for the power-user
+#
+# Copyright (C) 2025 Aaron Fiore (Founder, Evergreen Crypto LLC)
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+include ../../ethereum-based-shared.rules
+
+# vim: sw=2 sts=2 si ai et

container/src/hledger-flow/accounts/ledger/template/ledger/arbitrum/preprocess

@@ -0,0 +1 @@
+../../ethereum-based-shared.bash

container/src/hledger-flow/accounts/ledger/template/ledger/base/ledger-base.rules

@@ -0,0 +1,20 @@
+# docker-finance | modern accounting for the power-user
+#
+# Copyright (C) 2025 Aaron Fiore (Founder, Evergreen Crypto LLC)
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+include ../../ethereum-based-shared.rules
+
+# vim: sw=2 sts=2 si ai et

container/src/hledger-flow/accounts/ledger/template/ledger/base/preprocess

@@ -0,0 +1 @@
+../../ethereum-based-shared.bash

container/src/hledger-flow/accounts/ledger/template/ledger/optimism/ledger-optimism.rules

@@ -0,0 +1,20 @@
+# docker-finance | modern accounting for the power-user
+#
+# Copyright (C) 2025 Aaron Fiore (Founder, Evergreen Crypto LLC)
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+include ../../ethereum-based-shared.rules
+
+# vim: sw=2 sts=2 si ai et

container/src/hledger-flow/accounts/ledger/template/ledger/optimism/preprocess

@@ -0,0 +1 @@
+../../ethereum-based-shared.bash

container/src/hledger-flow/accounts/ledger/template/ledger/polygon/ledger-polygon.rules

@@ -0,0 +1,20 @@
+# docker-finance | modern accounting for the power-user
+#
+# Copyright (C) 2025 Aaron Fiore (Founder, Evergreen Crypto LLC)
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+include ../../ethereum-based-shared.rules
+
+# vim: sw=2 sts=2 si ai et

container/src/hledger-flow/accounts/ledger/template/ledger/polygon/preprocess

@@ -0,0 +1 @@
+../../ethereum-based-shared.bash