feat: async insight generation with SQLite job tracking

- Add insight_generation_jobs table migration and DAO
- Implement job lifecycle: create_or_get_active, complete, fail, cancel
- Refactor POST /insights/generate and /agentic to async spawn with timeout
- Add GET /insights/generation/status endpoint with job_id and file_path lookup
- Use String for enum fields in Diesel models to avoid private Bound type
- Add from_str() helpers on InsightJobStatus and InsightGenerationType
- Fix update_training_messages to return Result<usize, DbError>
- 7/7 DAO unit tests passing

src/ai/insight_chat.rs

@@ -107,6 +107,11 @@ impl InsightChatService {
         }
     }
 
+    /// Accessor for the insight DAO (used by async job completion).
+    pub fn insight_dao(&self) -> &Arc<Mutex<Box<dyn InsightDao>>> {
+        &self.insight_dao
+    }
+
     /// Load the rendered transcript for chat-UI display. Filters internal
     /// scaffolding (system message, tool turns, tool-dispatch-only assistant
     /// messages) and drops base64 images from user turns to keep payloads
@@ -522,8 +527,17 @@ impl InsightChatService {
         } else {
             let cx = opentelemetry::Context::new();
             let mut dao = self.insight_dao.lock().expect("Unable to lock InsightDao");
-            dao.update_training_messages(&cx, req.library_id, &normalized, &json)
+            let rows = dao
+                .update_training_messages(&cx, req.library_id, &normalized, &json)
                 .map_err(|e| anyhow!("failed to persist chat history: {:?}", e))?;
+            if rows == 0 {
+                log::warn!(
+                    "update_training_messages updated 0 rows for {} (lib {}), \
+                     concurrent regenerate likely flipped is_current",
+                    normalized,
+                    req.library_id
+                );
+            }
         }
 
         Ok(ChatTurnResult {
@@ -590,8 +604,17 @@ impl InsightChatService {
 
         let cx = opentelemetry::Context::new();
         let mut dao = self.insight_dao.lock().expect("Unable to lock InsightDao");
-        dao.update_training_messages(&cx, library_id, &normalized, &json)
+        let rows = dao
+            .update_training_messages(&cx, library_id, &normalized, &json)
             .map_err(|e| anyhow!("failed to persist truncated history: {:?}", e))?;
+        if rows == 0 {
+            log::warn!(
+                "update_training_messages (rewind) updated 0 rows for {} (lib {}), \
+                 concurrent regenerate likely flipped is_current",
+                normalized,
+                library_id
+            );
+        }
         Ok(())
     }
 
@@ -851,8 +874,17 @@ impl InsightChatService {
         } else {
             let cx = opentelemetry::Context::new();
             let mut dao = self.insight_dao.lock().expect("Unable to lock InsightDao");
-            dao.update_training_messages(&cx, req.library_id, &normalized, &json)
+            let rows = dao
+                .update_training_messages(&cx, req.library_id, &normalized, &json)
                 .map_err(|e| anyhow!("failed to persist chat history: {:?}", e))?;
+            if rows == 0 {
+                log::warn!(
+                    "update_training_messages (stream) updated 0 rows for {} (lib {}), \
+                     concurrent regenerate likely flipped is_current",
+                    normalized,
+                    req.library_id
+                );
+            }
         }
 
         let _ = tx