readme: document trust circle design
readme: tone down trust circle language to match existing style
remove forum_enabled toggle: subscribing IS trusting, no intermediate state
- Tag bloom filter as primary peer discovery (2048 bits x 3 hashes)
- Filter table gossip for transitive peer discovery
- Scoped queries for on-demand tag lookup
- Liveness tracking + peer eviction (5 failures, 7-day TTL)
- Topic subscriptions filter content sync at both ends
- Two-theme CSS system (default minimal + kodama2)
- Status bar on all pages (topics, peers, filters)
- Bracketless tags, grouped moderation page, cleaner forms
- Match main site heading level (h1 -> h2)
