Add bounded definition and reference navigation for current source drafts

Preserve loaded draft bytes and model history, reject stale workspace and input events, and keep captured Escape under modal priority. Verified 181 focused Windows tests and strict desktop Clippy on exact inputs4; earlier full737 scope and component/native preparation evidence are archived separately. Native navigation acceptance remains pending.

crates/oa-desktop/src/views.rs

@@ -1,3 +1,4 @@
+mod source_symbols;
 pub(crate) mod traceability;
 use crate::{
     app::{App, Choice, FileOperation, Message, Page, Pending},
@@ -1113,8 +1114,12 @@ fn source(app: &App) -> View<'_, Message> {
         }
     }
     let editor = widget::text_editor(&app.source_editor)
-        .id("source-editor")
+        .id(app.source_editor_id())
         .on_action(Message::SourceEdit)
+        .key_binding({
+            let context = app.source_symbol_context();
+            move |press| source_binding(press, &context)
+        })
         .font(Font::MONOSPACE)
         .size(14)
         .padding(16)
@@ -1123,8 +1128,7 @@ fn source(app: &App) -> View<'_, Message> {
             app.source_snapshot.clone(),
             crate::highlight::format,
         );
-    column![
-        container(
+    let header = container(
             column![
                 row![
                     container(heading(
@@ -1167,17 +1171,83 @@ fn source(app: &App) -> View<'_, Message> {
                     "Undo text affects this file's draft. Model Undo restores accepted files together (100 changes / about 32 MiB)."
                 }),
                 navigation,
+                row![
+                    action("Definition · F12", app.source_symbol_message(crate::source_navigation::SymbolEvent::Query(crate::source_navigation::query::Action::Definition))),
+                    action("References · Shift F12", app.source_symbol_message(crate::source_navigation::SymbolEvent::Query(crate::source_navigation::query::Action::References))),
+                    button(text("Back · Alt ←").size(12)).padding([8, 10]).style(style::nav)
+                        .on_press_maybe((app.source_symbols.back.iter().any(|entry| entry.session == app.source_workspace.session())).then(|| app.source_symbol_message(crate::source_navigation::SymbolEvent::Back))),
+                ].spacing(7),
                 scrollable(diagnostics)
                     .height((visible_diagnostics as f32 * 32.).min(132.))
             ]
             .spacing(12)
         )
-        .padding(18),
-        widget::sensor(editor).key((app.source_workspace.active.clone(),app.source_jump))
-            .on_show(|_| Message::SourceViewport).on_resize(|_| Message::SourceViewport)
+        .padding(18);
+    let editor = widget::sensor(editor)
+        .key((
+            app.source_workspace.active.clone(),
+            app.source_reveal_ticket(),
+        ))
+        .on_show({
+            let ticket = app.source_reveal_ticket();
+            move |_| Message::SourceViewport(ticket)
+        })
+        .on_resize({
+            let ticket = app.source_reveal_ticket();
+            move |_| Message::SourceViewport(ticket)
+        });
+    let workspace: View<'_, Message> = if app.source_symbols.open {
+        row![
+            container(editor).width(Fill).height(Fill),
+            container(scrollable(source_symbols::panel(app)))
+                .width(300)
+                .height(Fill),
+        ]
+        .height(Fill)
+        .into()
+    } else {
+        container(editor).width(Fill).height(Fill).into()
+    };
+    column![
+        container(scrollable(header)).max_height((app.window_size.height * 0.42).max(180.)),
+        workspace,
     ]
+    .height(Fill)
     .into()
 }
+fn source_binding(
+    press: widget::text_editor::KeyPress,
+    context: &crate::source_navigation::SymbolContext,
+) -> Option<widget::text_editor::Binding<Message>> {
+    use crate::source_navigation::{SymbolEvent, query::Action};
+    use iced::keyboard::{Key, key::Named};
+    use widget::text_editor::{Binding, Status};
+    if matches!(press.status, Status::Focused { .. })
+        && !press.modifiers.control()
+        && !press.modifiers.logo()
+    {
+        let event = match &press.key {
+            Key::Named(Named::F12) if !press.modifiers.alt() => {
+                Some(SymbolEvent::Query(if press.modifiers.shift() {
+                    Action::References
+                } else {
+                    Action::Definition
+                }))
+            }
+            Key::Named(Named::ArrowLeft) if press.modifiers.alt() && !press.modifiers.shift() => {
+                Some(SymbolEvent::Back)
+            }
+            _ => None,
+        };
+        if let Some(event) = event {
+            return Some(Binding::Custom(Message::SourceSymbols(
+                context.clone(),
+                event,
+            )));
+        }
+    }
+    Binding::from_key_press(press)
+}
 fn checks(app: &App) -> View<'_, Message> {
     let issues = &app.model_issues;
     let mut out = column![heading(