fix: offline report shows identity names in trace tooltips

- Load trace_to_identity mapping from SQLite face_detections
- Query identity names from identities table
- Show 'identity: PERSON_xxx' in each trace bar tooltip
- Works in both full view and --identity filtered view

scripts/render_offline_report.py

@@ -75,6 +75,19 @@ density = {r[0]: r[1] for r in c.fetchall()}
 c.execute(f"SELECT COUNT(*) FROM face_detections WHERE 1=1{identity_filter}", identity_params)
 total_detections = c.fetchone()[0]
 
+# Trace-to-identity mapping (for tooltips)
+trace_to_identity = {}
+c.execute("SELECT DISTINCT trace_id, identity_id FROM face_detections WHERE trace_id IS NOT NULL AND identity_id IS NOT NULL")
+for tid, iid in c.fetchall():
+    trace_to_identity[tid] = iid
+# Get identity names
+id_names = {}
+if trace_to_identity:
+    unique_ids = set(trace_to_identity.values())
+    placeholders = ",".join(["?" for _ in unique_ids])
+    c.execute(f"SELECT id, name FROM identities WHERE id IN ({placeholders})", list(unique_ids))
+    id_names = {r[0]: r[1] for r in c.fetchall()}
+
 # Identity info
 identity_info = None
 if IDENTITY is not None:
@@ -214,7 +227,12 @@ def build_html():
         width = max(3, int((t1 - t0) / duration * (w_px - 20)))
         top = i * (bar_h + 1) + 5
         opacity = 1.0 if cnt > 5 else 0.3
-        h.append('<span class="bar" style="left:{}px;top:{}px;width:{}px;height:{}px;opacity:{}" title="T{}: {:.0f}s–{:.0f}s, {} faces"></span>'.format(left, top, width, bar_h, opacity, tid, t0, t1, cnt))
+        identity_note = ""
+        iid = trace_to_identity.get(tid)
+        if iid and iid in id_names:
+            identity_note = ", identity: {}".format(id_names[iid])
+        h.append('<span class="bar" style="left:{}px;top:{}px;width:{}px;height:{}px;opacity:{}" title="T{}: {:.0f}s–{:.0f}s, {} faces{}"></span>'.format(
+            left, top, width, bar_h, opacity, tid, t0, t1, cnt, identity_note))
     h.append('</div>')
     
     # 3. Top identities