Add manual title override for 03/09 (was showing as blank)

LinkedIn's export has no caption text for this post, so it fell back to
"(no text — image/video-only post)" instead of its actual content, "Come
meet us at SNIB2026" — looked like a missing/unaudited post even though
it was already fully audited underneath.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app.py

@@ -38,6 +38,7 @@ MANUAL_POST_TITLES = {
     "2026-07-09": "How it all started",
     "2026-07-14": "Time resolution",
     "2026-08-13": "TXservices measurement at a fraction of the cost",
+    "2026-09-03": "Come meet us at SNIB2026",
 }
 
 # TXproducts resharing someone else's post, not a post in TXproducts' own voice — excluded