Notes and highlights are on the roadmap — you'll be able to annotate as you read.
The social discovery angle is interesting. Hutch is deliberately private for now but curated recommendations from real readers with genuine notes is a different thing from algorithmic suggestions. Worth thinking about.
On the free tier: the first 100 users get free access, no time limit.
I haven't tried Shiori, I'll take a look.
Welcome to Hutch!