fix(query): Preserve case for Variant MapAccess in computed columns

[b41sh]

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Summary

This PR addresses a bug where MapAccess field names within VARIANT computed columns were incorrectly converted to lowercase, leading to NULL values when the original VARIANT data used case-sensitive field names. In the following example the field identifier (videoInfo) was being implicitly converted to lowercase (videoinfo).

CREATE TABLE test(
    id INT,
    data VARIANT,
    name STRING AS (data:videoInfo:name::string) STORED,
    duration INT AS(DATA:videoInfo:duration::int) STORED
);

INSERT INTO test VALUES(1, '{"videoInfo":{"name":"H264","duration":10}}'),(2, '{"videoInfo":{"name":"H265","duration":20}}');

# main branch
SELECT * FROM test;
╭────────────────────────────────────────────────────────────────────────────────────────────────────╮
│        id       │                     data                    │       name       │     duration    │
│ Nullable(Int32) │              Nullable(Variant)              │ Nullable(String) │ Nullable(Int32) │
├─────────────────┼─────────────────────────────────────────────┼──────────────────┼─────────────────┤
│               1 │ {"videoInfo":{"duration":10,"name":"H264"}} │ NULL             │            NULL │
│               2 │ {"videoInfo":{"duration":20,"name":"H265"}} │ NULL             │            NULL │
╰────────────────────────────────────────────────────────────────────────────────────────────────────╯

# This PR
SELECT * FROM test;
╭────────────────────────────────────────────────────────────────────────────────────────────────────╮
│        id       │                     data                    │       name       │     duration    │
│ Nullable(Int32) │              Nullable(Variant)              │ Nullable(String) │ Nullable(Int32) │
├─────────────────┼─────────────────────────────────────────────┼──────────────────┼─────────────────┤
│               1 │ {"videoInfo":{"duration":10,"name":"H264"}} │ H264             │              10 │
│               2 │ {"videoInfo":{"duration":20,"name":"H265"}} │ H265             │              20 │
╰────────────────────────────────────────────────────────────────────────────────────────────────────╯

This PR also add some logs and remove some unused comments for inverted index.

• fixes: #[Link the issue here]

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):

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🤖 CI Job Analysis

Workflow: 18672381196

📊 Summary

• Total Jobs: 83
• Failed Jobs: 2
• Retryable: 0
• Code Issues: 2

❌ NO RETRY NEEDED

All failures appear to be code/test issues requiring manual fixes.

🔍 Job Details

• ❌ linux / sqllogic / standalone (base, 2c8g, hybrid): Not retryable (Code/Test)
• ❌ linux / sqllogic / cluster (base, 2c8g, 2, hybrid): Not retryable (Code/Test)

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