fix(query): fix row access policy parameter order and case sensitivity

[TCeason]

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Summary

This commit fixes three critical bugs in row access policy that caused
incorrect filtering behavior with multi-parameter policies.

Issue 1: Parameter case sensitivity (storage)
Parameter names were stored with original case but looked up with
lowercase, causing HashMap mismatches.

Fix: Normalize parameter names to lowercase at creation time to ensure
case-insensitive matching (mirrors masking policy fix).

Issue 2: Parameter case sensitivity (lookup)
When replacing parameters in policy body expressions, the lookup key
used original case while args_map keys were lowercase.

Fix: Normalize lookup keys to lowercase when replacing parameters.

Issue 3: Parameter order not preserved
Using BTreeMap in protobuf serialization sorted parameters alphabetically,
breaking multi-parameter policies where order matters.

Example bug:
CREATE ROW ACCESS POLICY rap AS (UserId, Department) ...
ALTER TABLE t ADD ROW ACCESS POLICY rap ON (c1, c2);

Expected mapping: c1 -> UserId, c2 -> Department Actual mapping: c1 -> Department, c2 -> UserId (sorted!) 

Fix: Add args_v2 field using repeated message to preserve order, with
backward compatibility for old args map field.

Changes:

• Add RowAccessPolicyArg message and args_v2 field to protobuf
• Update FromToProto to prioritize args_v2 with fallback to args
• Normalize parameter names at creation (row_access_policy.rs)
• Normalize parameter names at lookup (table.rs)
• Add regression test for multi-parameter mixed-case scenario

Fixes parameter substitution in row access policies.

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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This change is 

[drmingdrmer]

@drmingdrmer reviewed 8 of 8 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @TCeason)