Fix bug causing IIIF image slider view all links to be broken in AI mode

[kdid]

Summary

When AI mode is enabled, the "View All" links on the IIIF image sliders are linking to a blank page of search results and behind the scenes the search query is returning a 400 error.

Root cause

The hybrid search request body included an inline search_pipeline definition alongside the ?search_pipeline=dc-v2-work-pipeline URL parameter. The API uses the URL parameter to specify the pipeline, and sending a conflicting inline definition in the body caused the 400.

Changes

• Remove inline search_pipeline from request body as the URL parameter is the correct mechanism for this API and is sufficient on its own
• Remove model_id from neural sub-query because the API injects the correct model ID server-side if not provided
• Move facet filters inside hybrid sub-queries becasue post_filter applies after scoring, so filters on collection and subject weren't constraining the neural query's candidate pool; pushing them into each sub-query ensures the K nearest neighbors are drawn from the correct filtered set
• Gate post_filter on non-AI queries which keeps existing filter behavior for standard keyword search unchanged