fix: clarify conflict pane roles and status indicators

Use Resolution and Other version borders, omit branch/path metadata,
and show unsaved output state only on the writable pane. Track native
explorer conflict C from authoritative jj state across draft/check/error
transitions and clear it only after confirmed resolution.

Focused resolver and save tests pass; live terminal labels and explorer
verified without saving the mock conflicts. Full library run: 795 pass,
one unrelated async plugin fixture_barrier startup failure.

src/files.rs

@@ -101,6 +101,7 @@ pub struct FilePicker {
     tree_searching: bool,
     warning: Option<String>,
     repository_changes: Vec<WorkingFileChange>,
+    conflicted_paths: HashSet<PathBuf>,
     has_virtual_entries: bool,
 }
 
@@ -306,6 +307,7 @@ impl FilePicker {
             tree_searching: false,
             warning,
             repository_changes: Vec::new(),
+            conflicted_paths: HashSet::new(),
         };
         for root in roots {
             let tree = picker.compact(root, None);
@@ -917,12 +919,28 @@ impl FilePicker {
         topology_changed || metadata_changed
     }
 
+    /// Last authoritative conflict state, independent of ordinary change status.
+    pub fn is_conflicted(&self, path: &Path) -> bool {
+        self.conflicted_paths.contains(path)
+    }
+
+    pub(crate) fn set_conflicted(&mut self, path: &Path, conflicted: bool) {
+        if conflicted {
+            if !self.conflicted_paths.contains(path) {
+                self.conflicted_paths.insert(path.to_owned());
+            }
+        } else {
+            self.conflicted_paths.remove(path);
+        }
+    }
+
     pub(crate) fn replace_paths(&mut self, paths: impl IntoIterator<Item = (usize, PathBuf)>) {
         self.replace_catalog(Self::from_paths(self.root.clone(), paths));
     }
 
     fn replace_catalog(&mut self, mut replacement: Self) {
         replacement.presentation = self.presentation;
+        replacement.conflicted_paths = std::mem::take(&mut self.conflicted_paths);
         let by_path: HashMap<_, _> = replacement
             .nodes
             .iter()