[AB#46836](https://sqlclientdrivers.visualstudio.com/c6d89619-62de-46a0-8b46-70b92a84d85e/_workitems/edit/46836)

### Summary

`tests/test_008_auth.py` added a top-level `from azure.core.credentials
import TokenCredential` (introduced with the `token_provider` work in
#603). That import runs at module-collection time — before the autouse
`setup_azure_identity` fixture injects its mock `azure.*` modules into
`sys.modules` — so in build/validation stages that install a minimal
dependency set (no `azure-identity`/`azure-core`), pytest aborts the
whole module with:

```
ModuleNotFoundError: No module named 'azure'
  tests/test_008_auth.py:32: in <module>
    from azure.core.credentials import TokenCredential
```

This wraps only that one top-level import in a `try/except ImportError`
guard (falling back to `TokenCredential = None`) so the module collects
even when `azure-core` is absent. The two tests in
`TestTokenProviderProtocol` that genuinely need the real
`runtime_checkable` Protocol are marked
`@pytest.mark.skipif(TokenCredential is None, ...)`; the third
scope-constant test does not use `TokenCredential` and continues to run.

All other `azure.*` imports in this file are function-local and already
resolve to the fixture's `sys.modules` mocks, so no other changes are
needed. When `azure-core` is installed (the normal path), behavior is
unchanged and both protocol tests run.

No production code is touched — test-only hardening.

### Work Item / Issue Reference

>
[AB#47087](https://sqlclientdrivers.visualstudio.com/c6d89619-62de-46a0-8b46-70b92a84d85e/_workitems/edit/47087)

-------------------------------------------------------------------
### Summary

Release mssql-python v1.13.0.

Version bump to 1.13.0. Updates `mssql_python/__init__.py`, `setup.py`,
`PyPI_Description.md`, and the README "Important Note" section. Bundled
`mssql_py_core` bumped from 0.1.7 to 0.1.8 (no source/API changes —
dev-nightly to stable pin).

#### Enhancements

- **ODBC driver ships exclusively via `mssql-python-odbc` (Phase 2)** —
The `libs/` fallback introduced in v1.12.0 has been removed.
`mssql-python` now hard-depends on `mssql-python-odbc==18.6.2.1`; `pip
install mssql-python` still pulls the driver package transparently.
Smaller wheels; driver binaries managed independently (#693).
- **Apache Arrow bulk copy** — New `Cursor.bulkcopy_arrow(table_name,
source)` method for high-performance bulk loading from `pyarrow.Table` /
`RecordBatch` / Arrow C Data Interface sources; classic `bulkcopy()` now
raises `TypeError` for Arrow inputs and steers users to the new method
(#665).
- **`token_provider=` parameter for Azure Identity credentials** —
`connect()` accepts any credential with a `.get_token(scope)` method
(`DefaultAzureCredential`, `AzureCliCredential`,
`ManagedIdentityCredential`, …). Mutually exclusive with
`Authentication=` in the connection string (#603, issue #577).
- **Identity-aware connection pooling with token-expiry refresh** — Pool
now keys on security context, preventing cross-identity connection
leaks; token acquisition deferred to pool-misses; connections with
near-expiry tokens refreshed automatically (#660, issues #651, #659).

#### Bug Fixes

- **Silent zero-row `executemany` batches on late NULLs** — Fixed
numeric array parameter binding paths
(`TINYINT`/`SMALLINT`/`INT`/`FLOAT`) that left indicator slots
uninitialized when a NULL appeared partway through the batch (#702,
issue #670).
- **`SQL_WVARCHAR` output converter applied as catch-all to non-string
columns** — Fallback now gated on `str`/`bytes` mapped types (#692,
issue #691).
- **Integer-keyed output converters silently never fired** —
`add_output_converter(SQL_DECIMAL, ...)` and other integer SQL type code
keys now dispatch correctly (pyodbc parity) (#690, issue #684).
- **`RecordBatchReader.Close()` for Arrow result sets** —
`Cursor.arrow_reader()` now returns a wrapper whose `.close()` releases
server-side resources and leaves the parent cursor usable (#644, issue
#643).
- **`AttributeError` in `Cursor.__del__` on partially-initialized
cursor** — `__init__` sets `closed`/`hstmt` before any raise; `__del__`
uses correct `sys.is_finalizing()` guard (#646, issue #642).

#### Version Bump

- `mssql_python/__init__.py`: `__version__ = "1.13.0"`
- `setup.py`: `version="1.13.0"`
- `PyPI_Description.md`: `## What's new in v1.13.0` section refreshed
- `README.md`: "Important Note" updated for Phase 2 (no more `libs/`
fallback, `mssql-python-odbc==18.6.2.1`)

resolves the cursor.py conflict from #665, which moved the shared bulkcopy
validation into _bulkcopy_core_and_validate. the timeout fix now lives in that
single helper, so it covers bulkcopy and bulkcopy_arrow at once.

also updates test_024's timeout_non_positive, which asserted the old behaviour,
and adds _token_provider to the new mock cursor for the #603 token_provider path.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>