Add fenix_blast_base_trades

[Hosuke]

Docs:

1. https://docs.fenixfinance.io/fenix/the-most-powerful-dex-on-blast/the-unified-amm
2. https://docs.fenixfinance.io/fenix/additional-information/contracts

Contribution type

Please check the type of contribution this pull request is for:

• New spell(s)
• Adding to existing spell lineage
• Bug fix

Note: You can safely discard any section below which doesn't apply based on selection above

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For new spell(s)

If you are building new spell(s), please provide the following information:

• Spell name(s): schema.table_name
• Description: [Detailed description of the new spell(s) and their purpose]
• Who are the new spell(s) for? [Internal team or general community]
• How will the new spell(s) be used downstream? [Description of downstream usage]
• Implementation details: [Information on how the spell(s) are implemented]
• Test instructions: [How to test the new spell(s)]
• Related issue(s): [Link to related issues, if any]

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For adding to existing spell lineage

If you are adding to an existing spell lineage, please provide the following information:

• Description: [Description of the changes made]

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For bug fixes

If you are fixing a bug, please provide the following information:

• Description: [Description of the bug fix]
• Steps to reproduce: [How to reproduce the bug]
• Implementation details: [Information on how the bug was fixed]
• Test instructions: [How to test the fix]
• Related issue(s): [Link to related issues, if any]

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Additional information

Please provide any additional information that might help us review your pull request:

• [Any additional information]

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Thank you for your contribution!

[Hosuke]

General Pair decoing is missing for fenix as well:
https://dune.com/queries/3898203?category=decoded_project&namespace=fenix&contract=Pair&blockchains=blast&id=fenix_blast.Pair_evt_Swap