App: crash reports and a log file; Help › Report a Bug (#107)

The desktop app installs the crash reporter and a log file at start
(both in a temporary folder in --control and CI runs, #266), journals
the window's commands (background jobs included) and every control
request's method, and ends the journal on a clean exit. A start after a
crash asks: "FieldCraft closed unexpectedly", Report It… or Not Now.

Help › Report a Bug (also Tools › Help and ui.start
diagnostics.bug_report) shows exactly what the GitHub bug form will be
filled with: the version, the OS, the last error, and for a crash where
it happened. Share my session adds the replayable commands, Include the
model file the model. Open GitHub Issue opens the form in the browser
through the system's opener; files to attach are saved to
bug-reports/<time>/ and a long session goes on the clipboard. Nothing is
sent without that click and the user's submit on GitHub.

The control channel answers the new prompts (crashed: report, close;
report_bug: set, close) and ui.inspect shows the draft; it never opens
the browser.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UhhZMBTviDQxZvwnyP89fo

crates/ui-egui/src/lib.rs

@@ -40,6 +40,7 @@ pub mod menu;
 pub mod navigation;
 pub mod palette;
 pub mod reply;
+pub mod report;
 pub mod results;
 pub mod results_panel;
 pub mod samples;
@@ -390,6 +391,10 @@ pub struct ModelApp {
     pub queued: std::collections::VecDeque<String>,
     /// The question the window is asking (unsaved changes, recover).
     pub prompt: Option<files::Prompt>,
+    /// Help › Report a Bug's form, while open ([`files::Prompt::ReportBug`]).
+    pub report: Option<report::ReportForm>,
+    /// The last error the status bar showed (what Report a Bug starts from).
+    pub last_error: Option<String>,
     /// A design opened over a model of another part, waiting for [`files::Prompt::Design`]'s answer.
     pub held: Option<files::Opened>,
     /// The window draws its own title bar and caption buttons (Windows, Linux).
@@ -468,6 +473,8 @@ impl ModelApp {
             loading: None,
             queued: std::collections::VecDeque::new(),
             prompt: None,
+            report: None,
+            last_error: None,
             held: None,
             custom_titlebar: false,
             integrated_titlebar: false,
@@ -783,6 +790,7 @@ impl ModelApp {
         let text = text.into();
         if error {
             log::warn!("{text}");
+            self.last_error = Some(text.clone());
         }
         self.status = Some(Status { text, error });
     }
@@ -1442,6 +1450,7 @@ impl ModelApp {
         egui::CentralPanel::default().frame(egui::Frame::NONE).show(ui, |ui| viewport::show(self, ui));
         palette::popup(self, ui.ctx());
         files::show(self, ui.ctx());
+        report::show(self, ui.ctx());
         if self.custom_titlebar {
             titlebar::resize_zones(ui);
         }