feat(hive): vendor Hive 3.1 metastore + fb303 Thrift IDL (#694)

Vendor the Apache Hive 3.1 standalone-metastore IDL and the fb303 helper
IDL it includes into thirdparty/hive_metastore/. These files are the
input for the C++ HMS client bindings, generated by a follow-up commit
that invokes `thrift --gen cpp` at build time.

Provenance:
* hive_metastore.thrift - apache/hive @ branch-3.1, standalone-metastore
* share/fb303/if/fb303.thrift - apache/thrift @ master, contrib/fb303

Both upstream files retain their Apache 2.0 license headers; only
trailing whitespace and final newlines were normalized by the
repository's pre-commit hooks. .github/.licenserc.yaml gains thirdparty/**
to paths-ignore so the license-eye check skips the vendored tree.

Author: MisterRaindrop

.github/.licenserc.yaml

@@ -31,5 +31,6 @@ header:
     - 'requirements.txt'
     - 'src/iceberg/util/murmurhash3_internal.*'
     - 'src/iceberg/test/resources/**'
+    - 'thirdparty/**'
 
   comment: on-failure

thirdparty/hive_metastore/README.md

@@ -0,0 +1,49 @@
+<!--
+  ~ Licensed to the Apache Software Foundation (ASF) under one
+  ~ or more contributor license agreements.  See the NOTICE file
+  ~ distributed with this work for additional information
+  ~ regarding copyright ownership.  The ASF licenses this file
+  ~ to you under the Apache License, Version 2.0 (the
+  ~ "License"); you may not use this file except in compliance
+  ~ with the License.  You may obtain a copy of the License at
+  ~
+  ~   http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing,
+  ~ software distributed under the License is distributed on an
+  ~ "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+  ~ KIND, either express or implied.  See the License for the
+  ~ specific language governing permissions and limitations
+  ~ under the License.
+-->
+
+# Vendored Hive Metastore Thrift IDL
+
+This directory contains vendored Thrift interface definitions used to generate
+the C++ Hive Metastore (HMS) client consumed by the `iceberg_hive` library. The
+files are copied verbatim from upstream Apache projects and remain under the
+Apache License, Version 2.0 (see `LICENSE` in the repository root). The only
+modification is the repository's pre-commit normalization (trailing whitespace
+stripped, single final newline); each file retains its original upstream license
+header in place.
+
+## Vendored sources
+
+Sources are pinned to immutable upstream tags and commit SHAs so the provenance
+is reproducible and future updates are deterministic.
+
+| File | Upstream | Tag | Commit |
+| --- | --- | --- | --- |
+| `hive_metastore.thrift` | [apache/hive](https://github.com/apache/hive) — `standalone-metastore/src/main/thrift/hive_metastore.thrift` | `rel/release-3.1.3` | [`04c1b307d1bbd1ae268ad47dc36ca4f50c6d9cd8`](https://github.com/apache/hive/blob/04c1b307d1bbd1ae268ad47dc36ca4f50c6d9cd8/standalone-metastore/src/main/thrift/hive_metastore.thrift) |
+| `share/fb303/if/fb303.thrift` | [apache/thrift](https://github.com/apache/thrift) — `contrib/fb303/if/fb303.thrift` | `v0.14.0` | [`8411e189b0af09e5baad34031555870cf692c1ad`](https://github.com/apache/thrift/blob/8411e189b0af09e5baad34031555870cf692c1ad/contrib/fb303/if/fb303.thrift) |
+
+`fb303.thrift` is the Facebook fb303 management service IDL, transitively
+included by `hive_metastore.thrift`. It was originally developed at Facebook,
+Inc. and contributed to the Apache Software Foundation under the Apache License,
+Version 2.0.
+
+## Updating
+
+Keep a single vendored IDL pinned to an immutable Hive release tag or commit.
+To update, re-fetch the file at the new upstream ref, refresh the table above
+with the new tag and commit SHA, and re-run the pre-commit hooks.