Change Summary

Add seven hash functions to the OTAP query-engine, per #2834:

• md5(): MD5 digest, backed by DataFusion's built-in crypto::md5 UDF.
• sha1(): SHA-1 digest, implemented as a custom ScalarUDF using the sha1 crate (DataFusion has no SHA-1 equivalent).
• sha512(): SHA-512 digest, backed by DataFusion's built-in crypto::sha512 UDF.
• fnv(): FNV-1a 64-bit hash, implemented as a custom ScalarUDF.
• murmur3(): MurmurHash3 32-bit hash, implemented as a custom ScalarUDF.
• xxh3(): XXH3 64-bit hash, implemented as a custom ScalarUDF using xxhash-rust.
• xxh128(): XXH3 128-bit hash, implemented as a custom ScalarUDF using xxhash-rust.

logs | extend attributes["hash"] = encode(md5(attributes["body"]), "hex")
logs | extend attributes["bucket"] = murmur3(attributes["service.name"])
logs | extend attributes["sig"] = xxh3(attributes["message"])

Files

• consts.rs, parser.rs: register all 7 functions as external functions with param_placeholders(1).
• pipeline/expr.rs: import DataFusion's md5(), sha512() and the new custom UDFs, add them to DataFusionFunctionDef::from_func_name with requires_dict_downcast: true.
• pipeline/functions/fnv.rs (new): custom FnvHashFunc - FNV-1a 64-bit, returns Int64.
• pipeline/functions/murmur3.rs (new): custom Murmur3HashFunc - MurmurHash3 32-bit, returns Int64.
• pipeline/functions/sha1.rs (new): custom Sha1Func using the sha1 crate, returns Binary.
• pipeline/functions/xxh3.rs (new): custom Xxh3Func using xxhash-rust, returns Int64.
• pipeline/functions/xxh128.rs (new): custom Xxh128Func using xxhash-rust, returns Binary (16 bytes big-endian).
• pipeline/functions.rs: module declarations and make_udf_function! registrations.
• crates/query-engine/Cargo.toml: add sha1 and xxhash-rust workspace dependencies.

What issue does this PR close?

• Closes sub-issue of [OPL/OTAP query-engine functions] additional hash algorithms #2834
• Part of [Epic] OPL/OTAP query engine scalar functions #2818

How are these changes tested?

Two layers of tests, all in this PR:

• Unit tests in each custom UDF module (fnv, murmur3, sha1, xxh3, xxh128): verify scalar string input, binary input, and null handling.
• pipeline::assign end-to-end tests for every function, exercising both OPL and KQL parsers through the full pipeline. Binary-returning functions (md5, sha1, sha512, xxh128) are wrapped with encode(..., "hex") and
  the output hex string is asserted. Integer-returning functions (fnv, murmur3, xxh3) assert the Int64 value directly.
  cargo xtask quick-check passes clean.

Are there any user-facing changes?

Yes users of the transform processor / query-engine can now call these hash functions in OPL/KQL programs:

logs | extend attributes["id"] = encode(sha1(attributes["body"]), "hex")
logs | extend attributes["bucket"] = fnv(attributes["service.name"])
logs | extend attributes["sig"] = xxh3(attributes["message"])
logs | extend attributes["hash"] = encode(xxh128(attributes["message"]), "hex")