feat(oxlint): Add --config-field CLI option

[leaysgur]

The same as #20138

However, I believe what can be done with my agent can also be done with yours, so feel free to close this PR. 🙏🏻 (There are no tests either and also failing...)

Prompts

## Task

Add `--config-field` CLI option to oxlint, mirroring the implementation in oxfmt (PR #20138).

This option lets users specify a top-level key to extract from the config object before deserializing into `Oxlintrc`. For example: `oxlint --config shared.json --config-field linter`.

## Requirements

- `--config-field` requires `--config` to be specified (use `bpaf` guard validation)
- Field extraction must happen at the `serde_json::Value` stage, before `Oxlintrc` deserialization (because `Oxlintrc` uses `#[serde(deny_unknown_fields)]`)
- Must work for both JSON/JSONC and JS/TS config files
- JSON and JS/TS paths must extract the field at the same layer (`config_loader.rs`), not at different stages

## Key design

Split `Oxlintrc::from_file` into `read_to_json_value` + `from_value` so callers can insert field extraction between reading and deserializing.

Change `JsConfigLoaderCb` to return raw `serde_json::Value` (`JsRawConfigResult`) instead of deserialized `Oxlintrc`, so `config_loader.rs` can uniformly apply field extraction for both config types.

Add a shared `extract_config_field(value, field, path)` helper in `config_loader.rs`.

## Files to modify

- `crates/oxc_linter/src/config/oxlintrc.rs` -- split `from_file` into `read_to_json_value` + `from_value`
- `apps/oxlint/src/command/lint.rs` -- add `--config-field` option with guard
- `apps/oxlint/src/js_config.rs` -- change callback to return raw values, extract `deserialize_js_config`
- `apps/oxlint/src/config_loader.rs` -- add `extract_config_field`, `load_with_field`, thread `config_field` through loading methods
- `apps/oxlint/src/lint.rs` -- pass `config_field` to loader
- `apps/oxlint/src/lsp/options.rs` -- add `configField` option
- `apps/oxlint/src/lsp/server_linter.rs` -- pass `config_field`, add to `needs_restart`
- `crates/oxc_language_server/README.md` -- document `configField` in table and JSON examples

[leaysgur]

• feat(oxlint): Add --config-field CLI option #20139 👈 (View in Graphite)
• main

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[codspeed-hq]

Merging this PR will not alter performance

✅ 4 untouched benchmarks
⏩ 52 skipped benchmarks¹

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_{Comparing 03-09-feat_oxlint_add_--config-field_cli_option (98dfa42) with main (36b2e56)}

Footnotes

1. 52 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[leaysgur]

We've decided to take a different approach, so closing.