stablecoins: prod_exclude placeholder models

[tomfutago]

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Description:

temp exclude 18 chains with only 0x00..00 placeholder address in core lists.

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quick links for more information:

• README.md
• spellbook docs
• CONTRIBUTING.md

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PR Summary

Temporarily excludes 18 chains with placeholder stablecoin lists and removes them from aggregated outputs.

• Adds tags: ['prod_exclude'] and switches post_hook to hide_spells() for balances/transfers/token models on: apechain, b3, boba, corn, degen, flow, henesys, megaeth, nova, peaq, sepolia, shape, sophon, superseed, tac, tron, viction, zkevm
• Introduces scaffolded core/extended transfers and balances models for these chains; token lists use 0x000...000 placeholders filtered out
• Updates aggregated views (stablecoins_balances, stablecoins_evm_balances, tokens_erc20_stablecoins, stablecoins_transfers, stablecoins_evm_transfers) to exclude the above chains

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