feat: add tag_dao to InsightGenerator for tag-based context enrichment

Threads SqliteTagDao through InsightGenerator and AppState (both default
and test_state). Adds Send+Sync bounds to TagDao trait with unsafe impls
for SqliteTagDao (always Mutex-protected) and TestTagDao (single-threaded).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/ai/insight_generator.rs

@@ -15,6 +15,7 @@ use crate::database::models::InsertPhotoInsight;
 use crate::database::{
     CalendarEventDao, DailySummaryDao, ExifDao, InsightDao, LocationHistoryDao, SearchHistoryDao,
 };
+use crate::tags::TagDao;
 use crate::memories::extract_date_from_filename;
 use crate::otel::global_tracer;
 use crate::utils::normalize_path;
@@ -45,6 +46,7 @@ pub struct InsightGenerator {
     calendar_dao: Arc<Mutex<Box<dyn CalendarEventDao>>>,
     location_dao: Arc<Mutex<Box<dyn LocationHistoryDao>>>,
     search_dao: Arc<Mutex<Box<dyn SearchHistoryDao>>>,
+    tag_dao: Arc<Mutex<Box<dyn TagDao>>>,
 
     base_path: String,
 }
@@ -59,6 +61,7 @@ impl InsightGenerator {
         calendar_dao: Arc<Mutex<Box<dyn CalendarEventDao>>>,
         location_dao: Arc<Mutex<Box<dyn LocationHistoryDao>>>,
         search_dao: Arc<Mutex<Box<dyn SearchHistoryDao>>>,
+        tag_dao: Arc<Mutex<Box<dyn TagDao>>>,
         base_path: String,
     ) -> Self {
         Self {
@@ -70,6 +73,7 @@ impl InsightGenerator {
             calendar_dao,
             location_dao,
             search_dao,
+            tag_dao,
             base_path,
         }
     }