feat(python): unify sync create_index API to match async API (#2882)

## Summary

- Transitions `LanceTable` and `RemoteTable` to use the unified
`create_index()` API matching `AsyncTable`
- Deprecates `create_scalar_index()` and `create_fts_index()` with
deprecation warnings
- Adds detection logic to distinguish legacy vs new API calls
- Adds `@overload` decorators for type checker compatibility
- Adds `accelerator` parameter to IVF config classes for GPU support

**New API:**
```python
table.create_index("vec", config=IvfPq(distance_type="l2"))
table.create_index("col", config=BTree())
table.create_index("text_col", config=FTS(with_position=True))
```

**Legacy API (deprecated):**
```python
table.create_index("l2", vector_column_name="vec")  # emits DeprecationWarning
table.create_scalar_index("col", index_type="BTREE")  # deprecated
table.create_fts_index("text_col")  # deprecated
```

Fixes #2879

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

python/python/tests/test_fts.py

@@ -215,11 +215,12 @@ def test_reject_legacy_tantivy_index(table):
 
 @pytest.mark.parametrize("with_position", [True, False])
 def test_create_inverted_index(table, with_position):
-    table.create_fts_index(
-        "text",
-        with_position=with_position,
-        name="custom_fts_index",
-    )
+    with pytest.warns(DeprecationWarning, match="create_fts_index"):
+        table.create_fts_index(
+            "text",
+            with_position=with_position,
+            name="custom_fts_index",
+        )
     indices = table.list_indices()
     fts_indices = [i for i in indices if i.index_type == "FTS"]
     assert any(i.name == "custom_fts_index" for i in fts_indices)