Correct the documented threadsafety level and rowcount behaviour

The module exports threadsafety=2 (connections may be shared across threads,
cursors may not), but the class docstring, a cursor comment, and DEVELOPMENT.md
still described it as 1. Update them to match. Also document in the rowcount
property docstrings that a SELECT reports the produced row count rather than -1,
since dqlite buffers the full result.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: antoineleclair

DEVELOPMENT.md

@@ -96,5 +96,5 @@ for.
 This package implements the DB-API 2.0 specification (PEP 249):
 
 - `apilevel = "2.0"`
-- `threadsafety = 1` (threads may share module, not connections)
+- `threadsafety = 2` (threads may share module and connections, not cursors)
 - `paramstyle = "qmark"` (question mark placeholders)

src/dqlitedbapi/aio/cursor.py

@@ -164,7 +164,9 @@ def completed_iterations(self) -> int:
 
     @property
     def rowcount(self) -> int:
-        """Rows affected by the last execute, or -1 if unknown/inapplicable."""
+        """Rows affected (DML) or, for SELECT, rows produced (dqlite buffers the
+        full result, unlike stdlib's -1); -1 if unknown/inapplicable.
+        """
         return self._rowcount
 
     @property

src/dqlitedbapi/connection.py

@@ -810,9 +810,10 @@ class Connection:
     mid-batch cancel without a surrounding BEGIN persists the completed
     iterations.
 
-    Thread-affinity: ``check_same_thread=True`` (default) enforces the
-    threadsafety=1 contract — foreign-thread calls raise
-    ProgrammingError. ``check_same_thread=False`` relaxes the
+    Thread-affinity: ``threadsafety`` is 2 (threads may share the module
+    and connections, but not cursors). ``check_same_thread=True``
+    (default) confines a connection to its creating thread — foreign-thread
+    calls raise ProgrammingError; ``check_same_thread=False`` relaxes the
     cross-thread check (the wire is already serialised by ``_op_lock``).
     Under it, the contract matches stdlib sqlite3: **share connections
     across threads; create one cursor per thread** (per-cursor result

src/dqlitedbapi/cursor.py

@@ -937,7 +937,9 @@ def description(self) -> _Description:
 
     @property
     def rowcount(self) -> int:
-        """Rows affected by the last execute; -1 if unknown / not applicable."""
+        """Rows affected (DML) or, for SELECT, rows produced (dqlite buffers the
+        full result, unlike stdlib's -1); -1 if unknown / not applicable.
+        """
         return self._rowcount
 
     @property
@@ -998,7 +1000,7 @@ def arraysize(self, value: int) -> None:
         # Closed-state guard on the SETTER only; the getter stays
         # permissive like peer drivers.
         self._check_closed()
-        # Enforce threadsafety=1 affinity. _check_thread short-circuits
+        # Enforce the default per-thread affinity. _check_thread short-circuits
         # under check_same_thread=False, where the cursor-per-thread
         # sub-contract becomes the caller's responsibility.
         self._connection._check_thread()