Omit verified default query parameters from extract.custom requests

[ebhills]

Simplify the URL produced by extract.custom while preserving its input/output, batching and endpoint behavior.

wrangles/extract.py currently always adds responseFormat, boolean flags and sort to the query. For a backend whose defaults have been verified, the default request should be:

POST /wrangles/extract/custom?model_id=<model_id>

An override remains explicit, for example:

POST /wrangles/extract/custom?model_id=<model_id>&use_labels=True&sort=input_order

The input stays in the existing JSON request body. This is URL cleanup, not a fix for server memory pressure or an API body redesign.

Proposed contract

For the built-in pattern extractor, verify and explicitly encode these server defaults: responseFormat=array, use_labels=false, caseSensitive=false, extract_raw=false, use_spellcheck=false, sort=training_order.

• Normalize known parameter types deliberately, then omit only values proven equivalent to that backend's default.
• Preserve explicit non-default options and existing keyword-argument precedence. Never generically remove falsy values, zero, blank strings or unknown parameters; invalid inputs must not silently become defaults.
• Preserve the distinction between transport responseFormat and local output-shaping options such as output_format, first_element and include_empty_labels.
• Use the metadata already obtained by the caller to scope the optimization. Validate AI/custom/bespoke contracts independently and preserve existing explicit parameters where equivalence is unverified.
• Keep model ID, authentication, configured API base, JSON payload, batching and returned values unchanged.
• Document that meaningful diagnostic context comes from effective options and a request ID, not a long exception URL. Retain server error/request identifiers when exposed, without including credentials or input content.

Acceptance criteria

• Default built-in extraction produces the minimal URL above and returns the same results as the explicit-default form.
• Non-default booleans, sort, response format and extra keyword parameters survive serialization correctly.
• Invalid/falsy/unknown values preserve existing validation semantics.
• Scalar/list input, batching and output-shaping behavior remain unchanged.
• AI/bespoke handling has an explicit compatibility decision and regression coverage.
• The JavaScript client uses the same documented default contract.

Use mocked request assertions and small synthetic response fixtures; this change does not require production model data.