fix(hybrid): propagate SearchOpts filters to inner keyword/vector searches

[x64Nika]

Summary

hybridSearch() silently drops caller-provided type and exclude_slugs filter options when building searchOpts for inner searchKeyword / searchVector calls:

https://github.com/garrytan/gbrain/blob/master/src/core/search/hybrid.ts#L71

const searchOpts: SearchOpts = { limit: innerLimit, detail };

Any caller using hybridSearch(engine, query, { type: 'person' }) or { exclude_slugs: [...] } gets unfiltered results while believing the filter is applied — the outer hybridSearch never reads those fields again, and the inner searches never see them.

Fix

One-line spread before overriding limit / offset / detail:

const searchOpts: SearchOpts = { ...opts, limit: innerLimit, offset: 0, detail };

This preserves every caller-provided filter field (current and future — any field added to SearchOpts becomes automatically propagated, no additional plumbing).

offset is explicitly set to 0 on the inner searches because the outer hybridSearch slices the final result set at [offset, offset+limit] itself — propagating the caller's offset into the inner searches would double-apply it.

Test plan

Added test/hybrid-search-opts.test.ts with 4 regression tests covering:

• type filter propagates to searchKeyword
• exclude_slugs propagates
• limit is overridden to innerLimit (outer limit * 2) and offset is forced to 0
• undefined opts don't throw

All existing tests still pass (bun test test/search.test.ts test/search-limit.test.ts — 42 pass, 0 fail).

Happy to add similar tests on the vector path or integration-level tests if that would help. Also flagged as draft in case you'd prefer a different fix shape (e.g., explicit per-field spread instead of full ...opts).