feat(redis): add native JSON session storage for 4.1.0

- Add opt-in SESSION_REDIS_JSON storage for asyncio Redis backends.
- Check JSON command support at startup and reject JSON mode on Trio.
- Read legacy strings and migrate sessions on their next save.
- Validate JSON objects before transactional replacement and expiry.
- Preserve tagged serialization for datetime, tuple, and other types.
- Cover command contracts, error handling, and session round-trips.
- Document server requirements, permissions, and migration limits.
- Normalize indentation and whitespace across code, tests, and examples.
- Bump the package and lockfile to 4.1.0 and update the changelog.
- Refresh the locked pycparser dependency to 3.12.

tests/conftest.py

@@ -7,39 +7,39 @@ from quart_session import Session
 
 @pytest.fixture
 def app_factory():
-    """Builds a Quart app backed by an in-memory session store."""
+  """Builds a Quart app backed by an in-memory session store."""
 
-    def _factory(**config) -> Quart:
-        app = Quart(__name__)
-        app.secret_key = "test-secret-key"
-        app.config["SESSION_TYPE"] = "null"
-        app.config.update(config)
-        Session(app)
+  def _factory(**config) -> Quart:
+    app = Quart(__name__)
+    app.secret_key = "test-secret-key"
+    app.config["SESSION_TYPE"] = "null"
+    app.config.update(config)
+    Session(app)
 
-        # 'null' interface is a no-op store, give it a dict so that
-        # open_session() can actually find data again.
-        store: dict = {}
-        interface = app.session_interface
+    # 'null' interface is a no-op store, give it a dict so that
+    # open_session() can actually find data again.
+    store: dict = {}
+    interface = app.session_interface
 
-        async def _get(key: str, app: Optional[Quart] = None):
-            return store.get(key)
+    async def _get(key: str, app: Optional[Quart] = None):
+      return store.get(key)
 
-        async def _set(key: str, value, expiry: Optional[int] = None,
-                       app: Optional[Quart] = None):
-            store[key] = value
+    async def _set(key: str, value, expiry: Optional[int] = None,
+             app: Optional[Quart] = None):
+      store[key] = value
 
-        async def _delete(key: str, app: Optional[Quart] = None):
-            store.pop(key, None)
+    async def _delete(key: str, app: Optional[Quart] = None):
+      store.pop(key, None)
 
-        interface.get = _get
-        interface.set = _set
-        interface.delete = _delete
+    interface.get = _get
+    interface.set = _set
+    interface.delete = _delete
 
-        @app.route("/")
-        async def index():
-            session["hits"] = session.get("hits", 0) + 1
-            return {"hits": session["hits"], "sid": session.sid}
+    @app.route("/")
+    async def index():
+      session["hits"] = session.get("hits", 0) + 1
+      return {"hits": session["hits"], "sid": session.sid}
 
-        return app
+    return app
 
-    return _factory
+  return _factory