feat(sqlalchemy): document baseline test-suite requirements (ISSUE-46)

Add declarations for cte, window_functions, returning, insert_from_select,
on_update_or_delete_cascades, self_referential_foreign_keys,
unique/primary/foreign_key/index_reflection, temporary_tables, and
table_ddl_if_exists — all mirroring SQLite behavior (exclusions.open()).

These don't change effective behavior (SuiteRequirements already returns
open for most) but make the dqlite contract explicit. Running the
SQLAlchemy compliance suite later can tighten each as needed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: antoineleclair

src/sqlalchemydqlite/requirements.py

@@ -48,3 +48,69 @@ def two_phase_transactions(self) -> Any:
     def temp_table_reflection(self) -> Any:
         """SQLite supports temp table reflection."""
         return exclusions.open()
+
+    # --- Baseline declarations mirroring SQLite behavior ------------
+    # These don't change the effective default (SuiteRequirements already
+    # returns exclusions.open() for most), but make the dqlite contract
+    # explicit so a future maintainer running the SQLAlchemy compliance
+    # suite has a single source of truth to adjust.
+
+    @property
+    def cte(self) -> Any:
+        """Common Table Expressions (WITH)."""
+        return exclusions.open()
+
+    @property
+    def window_functions(self) -> Any:
+        """SQL window functions (OVER / PARTITION BY)."""
+        return exclusions.open()
+
+    @property
+    def returning(self) -> Any:
+        """RETURNING clause on DML."""
+        return exclusions.open()
+
+    @property
+    def insert_from_select(self) -> Any:
+        """INSERT INTO ... SELECT."""
+        return exclusions.open()
+
+    @property
+    def on_update_or_delete_cascades(self) -> Any:
+        """ON UPDATE/DELETE CASCADE foreign-key actions."""
+        return exclusions.open()
+
+    @property
+    def self_referential_foreign_keys(self) -> Any:
+        """Table references itself via foreign key."""
+        return exclusions.open()
+
+    @property
+    def unique_constraint_reflection(self) -> Any:
+        """Inspector reports UNIQUE constraints."""
+        return exclusions.open()
+
+    @property
+    def primary_key_constraint_reflection(self) -> Any:
+        """Inspector reports PRIMARY KEY constraints."""
+        return exclusions.open()
+
+    @property
+    def foreign_key_constraint_reflection(self) -> Any:
+        """Inspector reports FOREIGN KEY constraints."""
+        return exclusions.open()
+
+    @property
+    def index_reflection(self) -> Any:
+        """Inspector reports indexes."""
+        return exclusions.open()
+
+    @property
+    def temporary_tables(self) -> Any:
+        """CREATE TEMPORARY TABLE support (same as SQLite)."""
+        return exclusions.open()
+
+    @property
+    def table_ddl_if_exists(self) -> Any:
+        """CREATE TABLE IF NOT EXISTS / DROP TABLE IF EXISTS."""
+        return exclusions.open()