fix(nightshift): fix already-running race, Codex completion, and upstream compat

- Drop RunGuard before emitting run-completed event to prevent race
  where user clicks Run Now before RUNNING_PROJECTS is cleared
- Use has_content (text + tool_calls + content_blocks) instead of just
  full_content for Codex error/fallback checks — prevents false
  chat:error when Codex works via tools with no text output
- Add nightshift fields to new upstream Session constructor site

Author: Loa212

src-tauri/src/chat/codex.rs

@@ -1838,7 +1838,9 @@ pub fn tail_codex_output(
         }
     }
 
-    if !error_emitted && !error_lines.is_empty() && full_content.is_empty() {
+    let has_content = !full_content.is_empty() || !content_blocks.is_empty() || !tool_calls.is_empty();
+
+    if !error_emitted && !error_lines.is_empty() && !has_content {
         let error_text = error_lines.join("\n");
         log::warn!("Codex CLI error output for session {session_id}: {error_text}");
 
@@ -1855,7 +1857,7 @@ pub fn tail_codex_output(
     }
 
     // Fallback: process died silently with no content and no error emitted
-    if !error_emitted && !completed && full_content.is_empty() && cancelled {
+    if !error_emitted && !completed && !has_content && cancelled {
         log::warn!("Codex process died silently for session {session_id} with no output");
         let _ = app.emit_all(
             "chat:error",

src-tauri/src/chat/storage.rs

@@ -776,6 +776,9 @@ where
                 last_run_execution_mode: None,
                 label: None,
                 queued_messages: vec![],
+                source: None,
+                nightshift_check_id: None,
+                nightshift_run_id: None,
             }
         };
         hydrated_sessions.push(session);

src-tauri/src/nightshift/engine.rs

@@ -714,6 +714,16 @@ pub fn execute_run(params: &RunParams<'_>) {
         log::error!("Failed to save final nightshift run: {e}");
     }
 
+    log::trace!(
+        "Nightshift run {run_id} completed: status={:?}, checks={}",
+        run.status,
+        run.check_results.len()
+    );
+
+    // Release project lock BEFORE notifying frontend — prevents "already running"
+    // race where user clicks Run Now immediately after seeing the completion toast
+    drop(_guard);
+
     let _ = app.emit_all(
         "nightshift:run-completed",
         &RunCompletedEvent {
@@ -724,14 +734,6 @@ pub fn execute_run(params: &RunParams<'_>) {
             worktree_id: Some(worktree.id.clone()),
         },
     );
-
-    // _guard handles cleanup_run + mark_project_done on drop
-
-    log::trace!(
-        "Nightshift run {run_id} completed: status={:?}, checks={}",
-        run.status,
-        run.check_results.len()
-    );
 }
 
 /// Start a nightshift run in a background thread. Returns the run ID.