refactor: config early engine foundation

[gvozdvmozgu]

Summary

Stacked PR 1/10: this is the base PR for the config early stack and should be merged first.

• Introduce the public engine API foundation.
• Migrate LSP and WASM lint/format flows onto the engine API.
• Add safety coverage for CLI, LSP, and path discovery behavior.
• Repair config loading after the engine migration.

Testing

• cargo +1.96.1 fmt --check
• cargo +1.96.1 check -p sqruff-lib -p sqruff-cli-lib -p sqruff-lsp
• cargo +1.96.1 test -p sqruff --test none_format

[github-actions]

Benchmark for e83ce98

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Test	Base	PR	%
DepthMap::from_parent	58.9±1.14µs	59.1±1.37µs	+0.34%
fix_complex_query	12.1±0.06ms	12.1±0.18ms	0.00%
fix_superlong	114.1±3.46ms	115.3±3.82ms	+1.05%
parse_complex_query	4.1±0.05µs	4.1±0.10µs	0.00%
parse_expression_recursion	7.1±0.20µs	6.9±0.10µs	-2.82%
parse_simple_query	1054.9±16.29ns	1041.8±13.28ns	-1.24%

[github-actions]

Benchmark for 552f920

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Test	Base	PR	%
DepthMap::from_parent	59.6±0.60µs	58.9±0.82µs	-1.17%
fix_complex_query	12.1±0.17ms	12.0±0.09ms	-0.83%
fix_superlong	116.0±3.23ms	117.4±3.90ms	+1.21%
parse_complex_query	4.1±0.05µs	4.2±0.05µs	+2.44%
parse_expression_recursion	6.9±0.14µs	6.9±0.08µs	0.00%
parse_simple_query	1068.7±25.62ns	1054.0±15.19ns	-1.38%

[github-actions]

Benchmark for 7f83793

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Test	Base	PR	%
DepthMap::from_parent	59.7±0.75µs	59.1±1.11µs	-1.01%
fix_complex_query	12.0±0.05ms	12.0±0.34ms	0.00%
fix_superlong	123.8±4.58ms	123.4±5.98ms	-0.32%
parse_complex_query	4.1±0.08µs	4.1±0.04µs	0.00%
parse_expression_recursion	6.9±0.10µs	6.9±0.08µs	0.00%
parse_simple_query	1057.7±27.94ns	1031.0±19.52ns	-2.52%

[github-actions]

Benchmark for aad5891

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Test	Base	PR	%
DepthMap::from_parent	59.1±1.00µs	58.9±1.96µs	-0.34%
fix_complex_query	12.2±0.14ms	12.2±0.16ms	0.00%
fix_superlong	133.8±12.05ms	134.7±9.83ms	+0.67%
parse_complex_query	4.1±0.06µs	4.1±0.06µs	0.00%
parse_expression_recursion	7.0±0.10µs	6.8±0.11µs	-2.86%
parse_simple_query	1048.2±30.46ns	1050.3±32.57ns	+0.20%

[github-actions]

Benchmark for 955f270

Click to view benchmark

Test	Base	PR	%
DepthMap::from_parent	61.8±0.70µs	62.2±3.49µs	+0.65%
fix_complex_query	13.4±0.47ms	13.3±0.69ms	-0.75%
fix_superlong	202.3±14.71ms	195.5±10.40ms	-3.36%
parse_complex_query	4.2±0.15µs	4.2±0.05µs	0.00%
parse_expression_recursion	7.4±0.04µs	7.5±0.09µs	+1.35%
parse_simple_query	1058.5±6.53ns	1046.1±27.31ns	-1.17%

[gvozdvmozgu]

@copilot rebase

[Copilot]

@copilot rebase

Done — merged latest main into the branch and resolved the MODULE.bazel.lock conflict (commit 2ef0071a).

[github-actions]

Benchmark for a2a6694

Click to view benchmark

Test	Base	PR	%
DepthMap::from_parent	61.0±0.77µs	61.3±0.63µs	+0.49%
fix_complex_query	12.9±0.08ms	12.9±0.12ms	0.00%
fix_superlong	131.9±11.87ms	140.9±11.68ms	+6.82%
parse_complex_query	4.3±0.02µs	4.3±0.06µs	0.00%
parse_expression_recursion	7.4±0.04µs	7.4±0.07µs	0.00%
parse_simple_query	1068.3±11.27ns	1056.8±15.53ns	-1.08%

[github-actions]

Benchmark for 2fc9657

Click to view benchmark

Test	Base	PR	%
DepthMap::from_parent	58.7±2.72µs	59.9±2.65µs	+2.04%
fix_complex_query	12.0±0.10ms	12.1±0.10ms	+0.83%
fix_superlong	119.6±3.66ms	121.4±3.33ms	+1.51%
parse_complex_query	4.1±0.06µs	4.2±0.05µs	+2.44%
parse_expression_recursion	6.9±0.15µs	6.9±0.16µs	0.00%
parse_simple_query	1064.2±15.87ns	1045.7±10.83ns	-1.74%

[gvozdvmozgu]

@copilot rebase