feat: add Tencent GooseFS Table Master namespace implementation (Python)

[XuQianJin-Stars]

Closes #121

Summary

Add a new Lance Namespace implementation backed by Tencent Cloud GooseFS Table Master to the Python lance-namespace-impls package. GooseFS Table Master is a Lance-native metadata service exposed over gRPC and is purpose-built for Lance, so every registered table is a Lance table and no table_type=lance marker filtering is required on the client side.

This implementation acts as a thin pass-through layer that translates each Lance Namespace request into the corresponding gRPC request defined by the GooseFS Table Master schema, forwarded through the official goosefs-metastore-client library. It follows the same integration pattern already used for Hive, Glue, Iceberg, Polaris, and Unity in this repo.

Changes

• New GooseFSNamespace class in python/src/lance_namespace_impls/goosefs.py, registered as goosefs in LanceNamespaces.
• Two-level namespace hierarchy (database then table); identifier is forwarded verbatim to the Table Master.
• Configurable connection (uri, host, port, timeout, max_retries), authentication (authentication_enabled, username, impersonation_user), and namespace defaults (manifest_enabled, dir_listing_enabled).
• Operations: namespace Create/List/Describe/Drop/Exists; table Create/CreateEmpty/Declare/Register/List/Describe/Drop/Deregister/Exists/Rename; data plane Insert/MergeInsert/Delete/Update/Query/CountRows; schema evolution AddColumns/AlterColumns/DropColumns/UpdateSchemaMetadata; indexing CreateIndex/CreateScalarIndex/ListIndices/DescribeIndexStats/DropIndex; tags and versioning; transactions and query planning.
• New optional extra goosefs in python/pyproject.toml with goosefs-metastore-client==0.1.7, grpcio>=1.78, grpcio-status>=1.78.
• New Makefile targets lint-goosefs, install-goosefs, test-goosefs, integ-test-goosefs.
• Unit tests in python/tests/test_goosefs.py and integration tests in python/tests/test_goosefs_integration.py (auto-skipped when the service is unreachable).
• New docs page docs/src/goosefs.md and navigation entry in docs/src/.pages.

Testing

ruff format --check and ruff check pass on the whole python/ tree. python -m compileall succeeds for src/ and tests/. Unit tests pass with the goosefs extra installed. Integration tests pass against a live GooseFS Table Master.

User-facing changes

Purely additive: a new optional extra pip install lance-namespace[goosefs], a new impl name goosefs for LanceNamespaces.connect, and a new docs page. No existing implementation is modified.

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