refactor: rename app fai_studio -> chain_studio

Studio is the Ch∆In product's GUI, not a F∆I-vendor app. Rename the
Flutter package, all package: imports, and the build identity across
platforms: linux/windows CMake BINARY_NAME + project, Windows Runner.rc
fields, macOS PRODUCT_NAME / bundle id (ai.flemming.chain.chainStudio) /
.app + scheme BuildableName. Update the client-SDK + flow-editor deps to
their renamed chain_* packages (path + git URL). Company/copyright fields
now read Flemming.AI. flutter analyze: clean.

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

lib/data/friendly_error.dart

@@ -34,7 +34,7 @@ class FriendlyError {
 FriendlyError friendlyError(Object error, AppLocalizations l) {
   // We deliberately don't import package:grpc here so Studio
   // doesn't have to add it to its own pubspec — the dependency
-  // lives one layer down in fai_client_sdk. `GrpcError` has a
+  // lives one layer down in chain_client_sdk. `GrpcError` has a
   // stable `.code` (int) and `.message` (String?) shape; we
   // duck-type on those instead of an `is` check.
   final code = _intField(error, 'code');