P2-F: Community Detection & Graph Coverage Quotas (DELIVERS: topic-diverse hotpath)

[github-actions]

Why: Without community detection, a single dense topic can fill the entire page-tier quota, crowding out unrelated memories. Community quotas ensure the hotpath is both hot (high salience) and diverse (topic-representative).

• P2-F1: Add community detection to daydreamer/ClusterStability.ts

  • Implement lightweight label propagation on the Metroid neighbor graph
  • Run during idle passes when dirty-volume flags indicate meaningful structural change
  • Store community labels in PageActivity.communityId via MetadataStore.putPageActivity
  • Rerun when graph topology changes significantly (post-split, post-merge, post-full-recalc)

• P2-F2: Wire community labels into SalienceEngine promotion/eviction

  • selectEvictionTarget uses communityId to find weakest resident in the community bucket
  • Promotion checks community quota remaining before admitting
  • If community quota is full: candidate must beat weakest resident in that community
  • If community is unknown (communityId not yet set): place node in temporary pending pool borrowing from page-tier budget
  • Empty communities release their slots back to the page-tier budget

• P2-F3: Add community-aware eviction tests

  • tests/daydreamer/ClusterStability.test.ts
  • Test that a single dense community cannot consume all page-tier hotpath slots
  • Test that a new community (previously unknown) receives at least one slot
  • Test that an empty community releases its slots correctly
  • Test that label propagation converges and produces stable community assignments

Exit Criteria: Community-aware hotpath quotas active; topic diversity enforced; label propagation stable.