fix(kernel): cap pyarrow <23 on the sub-3.10 band so poetry lock resolves

The kernel's transitive pyarrow>=23.0.1,<24 conflicts with the
connector's own pyarrow>=14.0.1 (declared across 3.8–3.13) during
`poetry lock`: pyarrow>=23 dropped Python 3.9, so for the 3.8–3.10
slice poetry can't find a pyarrow satisfying both and version solving
fails ("pyarrow is forbidden" -> "databricks-sql-kernel is forbidden").
The kernel's python>=3.10 marker doesn't help because poetry unifies
the pyarrow constraint across the connector's declared pyarrow band,
not the kernel's.

Split the connector's pyarrow entry at 3.10 and cap the <3.10 band at
<23. This removes no installable version — the newest pyarrow with a
Python 3.9 wheel is 21.x — it just makes that physical fact explicit to
the solver, so the <3.10 band (capped, kernel absent) and the >=3.10
band (where the kernel can pull pyarrow up to <24) no longer overlap.
Verified `poetry lock` resolves the full dependency set with this
change.

Co-authored-by: Isaac
Signed-off-by: Vikrant Puppala <vikrant.puppala@databricks.com>

Author: vikrantpuppala

pyproject.toml

@@ -25,7 +25,16 @@ openpyxl = "^3.0.10"
 urllib3 = ">=1.26"
 python-dateutil = "^2.8.0"
 pyarrow = [
-    { version = ">=14.0.1", python = ">=3.8,<3.13", optional=true },
+    # The <3.10 band is capped at <23 because pyarrow>=23 dropped
+    # Python 3.9 (it requires >=3.10). Without the cap, poetry tries to
+    # unify this entry with the kernel's transitive pyarrow>=23.0.1,<24
+    # across the 3.8–3.10 slice and `poetry lock` fails ("pyarrow is
+    # forbidden"). The cap removes no installable version — the newest
+    # pyarrow with a 3.9 wheel is 21.x — it just makes that explicit to
+    # the solver so the optional [kernel] extra (python>=3.10) can
+    # coexist. See the kernel dep + [kernel] extra below.
+    { version = ">=14.0.1,<23", python = ">=3.8,<3.10", optional=true },
+    { version = ">=14.0.1", python = ">=3.10,<3.13", optional=true },
     { version = ">=18.0.0", python = ">=3.13,<3.14", optional=true },
     { version = ">=22.0.0", python = ">=3.14", optional=true }
 ]