normalizeGeneratedTitle only guarded emptiness and the none sentinel, so
when the tiny title model ignored the titling task and answered the first
user message, its full one-line reply became the session title verbatim.
Bound accepted titles to 80 chars / 12 words and return null past that,
deferring titling to the next user turn. Both the online and local-worker
paths funnel through this normalizer, so both are covered.
Fixes#7303
roboomp
294f32d6bc