fix(query): preserve arguments after identity cast elimination

[forsaken628]

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Summary

• Prevent scalar type checking from remapping an inner function's arguments onto the original call after an identity cast is eliminated
• Reuse checked arguments only when the checked expression still has the same root function and arity, including alias resolution

Tests

• Unit Test
• Logic Test
• Benchmark Test
• No Test - Explain why

Type of change

• Bug Fix (non-breaking change which fixes an issue)
• New Feature (non-breaking change which adds functionality)
• Breaking Change (fix or feature that could cause existing functionality not to work as expected)
• Documentation Update
• Refactoring
• Performance Improvement
• Other (please describe):

AI assistance

• AI usage: An AI coding agent assisted with implementation.
• Responsible human: @forsaken628
• The responsible human has read every line of this diff and can explain each change

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[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Compare against the rewritten argument list

For a nonconstant positional call such as as_decimal(variant_column, 10, 2), the earlier split_off(1) moves precision and scale into params, so the checked function has one argument while args still has three. This comparison therefore marks the valid checked root as mismatched, and the fallback constructs a scalar call containing both the new parameters and all three original arguments; the as_decimal factory accepts exactly one argument, so later type checking/evaluation rejects the query. Compare with the post-rewrite arguments and add a nonconstant regression alongside the positional syntax in tests/sqllogictests/suites/query/functions/02_0056_function_semi_structureds_as.test.

AGENTS.md reference: src/query/AGENTS.md:L8-L8

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