chore: rename H7CAD to Open CAD Studio

Joining the OpenAEC Foundation (open-aec.com). Crate/struct become
OpenCADStudio, user-facing strings use the spaced "Open CAD Studio"
form, repo URLs point to HakanSeven12/open-cad-studio. Logo (window
icon + assets/logo.svg) redrawn with OCS initials. Drop examples/
binaries — unused.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/app/cmd_result.rs

@@ -1,9 +1,9 @@
-use super::{Message, H7CAD};
+use super::{Message, OpenCADStudio};
 use crate::command::CmdResult;
 use acadrust::Handle;
 use iced::Task;
 
-impl H7CAD {
+impl OpenCADStudio {
     pub(super) fn apply_cmd_result(&mut self, result: CmdResult) -> Task<Message> {
         let i = self.active_tab;
         match result {