refactor(config): dedup query config inner/outer

[dantengsky]

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Summary

• Deduplicate query config by embedding outer::QueryConfig into inner::QueryConfig.common
• Preserve existing env override semantics by keeping the outer config flat (no nested common layer)
• Keep runtime-only fields scoped in inner config (tenant_id, node_id, node_secret, builtin/settings), and access configurable fields explicitly via query.common.*

Design Choice

• We intentionally avoid Deref/DerefMut from inner config to outer config.
• Deref is idiomatic mainly for pointer-like wrappers; using it here would blur domain boundaries between runtime-only and user-configurable fields.
• Explicit query.common.* access keeps field ownership and data source clear, improves readability/grep-ability, and makes future refactors safer.
• Avoiding DerefMut also prevents implicit mutable access paths that are easy to misuse in a large codebase.

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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