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>

pubspec.yaml

@@ -1,4 +1,4 @@
-name: fai_studio
+name: chain_studio
 description: "Ch∆In Studio — desktop GUI for the Ch∆In hub"
 publish_to: 'none'
 version: 0.70.0
@@ -17,8 +17,8 @@ dependencies:
   meta: any
 
   # Sibling package; will move to Forgejo path once published.
-  fai_client_sdk:
-    path: ../fai_client_sdk_dart
+  chain_client_sdk:
+    path: ../fai_chain_client_sdk_dart
   shared_preferences: ^2.5.5
   # Inline README rendering inside the Store detail sheet.
   # `flutter_markdown` is discontinued; `flutter_markdown_plus`
@@ -39,9 +39,9 @@ dependencies:
   # be replaced without touching the rest of Studio. Pin to a
   # commit (or branch) here; rebuild Studio to pick up
   # editor-side changes.
-  fai_studio_flow_editor:
+  chain_studio_flow_editor:
     git:
-      url: https://git.flemming.ai/fai/studio-flow-editor
+      url: https://git.flemming.ai/fai/chain-studio-flow-editor
       ref: main
 
 dev_dependencies:
@@ -55,8 +55,8 @@ dev_dependencies:
 # + `pub upgrade`. Comment the block out before tagging a Studio
 # release so the committed Git ref is what builds on Forgejo CI.
 dependency_overrides:
-  fai_studio_flow_editor:
-    path: ../fai_studio_flow_editor
+  chain_studio_flow_editor:
+    path: ../fai_chain_studio_flow_editor
 
 flutter:
   uses-material-design: true