chore: delete orphaned SearchTermsOperation files

Both files defined a SearchTermsOperation backed by `encryptBulk`
(storage encryption), but were never imported. The live
`createSearchTerms` API routes through
packages/protect/src/ffi/operations/deprecated/search-terms.ts —
which is marked `@deprecated` but actually uses the correct
`encryptQueryBulk` call. The orphans stayed invisible because before
protect-ffi 0.23.0 split storage/query types, both FFI calls returned
the same conflated shape.

Deleting the dead files so nobody edits them thinking they're live.

Author: freshtonic