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/io/print_to_printer.rs

@@ -28,7 +28,7 @@ pub async fn print_wires(
     plot_style: Option<PlotStyleTable>,
 ) -> Result<String, String> {
     // ── 1. Write to a named temp file ─────────────────────────────────────
-    let tmp_path = std::env::temp_dir().join("h7cad_print.pdf");
+    let tmp_path = std::env::temp_dir().join("open_cad_studio_print.pdf");
     pdf_export::export_pdf(
         &wires,
         &hatches,