feat(onboarding): "Project archive" PLC format + auto-detect from extension

A .projectarchive is neither PLCopen XML nor Structured Text, but the wizard's
format dropdown only offered those two — confusing when uploading a CODESYS
archive (found live during the demo).

- add PlcFormat::ProjectArchive (metadata only; processing is content-driven).
- wizard: add the "Project archive (.projectarchive)" option, and auto-select the
  format from the chosen file's extension (.projectarchive/.project → archive,
  .xml → PLCopen XML, .st/.exp/.scl → Structured Text).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

compliance-core/src/models/onboarding.rs

@@ -202,6 +202,9 @@ pub enum PlcFormat {
     PlcopenXml,
     /// IEC 61131-3 Structured Text source.
     StructuredText,
+    /// A CODESYS project archive (`.projectarchive` — a zip bundling the project
+    /// plus its referenced libraries and runtime; the source of the control-app SBOM).
+    ProjectArchive,
 }
 
 /// PLC-specific configuration for a [`ArtifactKind::PlcProject`] artifact.

compliance-dashboard/src/pages/onboarding.rs

@@ -264,6 +264,15 @@ pub fn OnboardingPage() -> Element {
                                     onchange: move |evt| {
                                         let Some(file) = evt.files().into_iter().next() else { return; };
                                         let name = file.name();
+                                        // Auto-detect the PLC format from the file extension.
+                                        let lname = name.to_ascii_lowercase();
+                                        if lname.ends_with(".projectarchive") || lname.ends_with(".project") {
+                                            new_plc_format.set("project_archive".to_string());
+                                        } else if lname.ends_with(".xml") || lname.ends_with(".plcopen") {
+                                            new_plc_format.set("plcopen_xml".to_string());
+                                        } else if lname.ends_with(".st") || lname.ends_with(".exp") || lname.ends_with(".scl") {
+                                            new_plc_format.set("structured_text".to_string());
+                                        }
                                         spawn(async move {
                                             if let Ok(bytes) = file.read_bytes().await {
                                                 new_file.set(Some((name, bytes.to_vec())));
@@ -278,8 +287,21 @@ pub fn OnboardingPage() -> Element {
                                     select {
                                         value: "{new_plc_format}",
                                         oninput: move |e| new_plc_format.set(e.value()),
-                                        option { value: "plcopen_xml", "PLCopen XML" }
-                                        option { value: "structured_text", "Structured Text" }
+                                        option {
+                                            value: "plcopen_xml",
+                                            selected: new_plc_format() == "plcopen_xml",
+                                            "PLCopen XML",
+                                        }
+                                        option {
+                                            value: "structured_text",
+                                            selected: new_plc_format() == "structured_text",
+                                            "Structured Text",
+                                        }
+                                        option {
+                                            value: "project_archive",
+                                            selected: new_plc_format() == "project_archive",
+                                            "Project archive (.projectarchive)",
+                                        }
                                     }
                                 }
                             }