EPIC: Social, communications and calendars

Programme: #1

Own cross-network feed normalization, transparent user-controlled ranking, destination-correct social writes, and email/calendar/contact/project actions.

## Child issues
- [ ] #85 SOC-01 — Unified feeds and cross-network normalization
- [ ] #86 SOC-02 — User-controlled feed ranking
- [ ] #87 SOC-03 — Social posting, replies, cross-posting and messaging
- [ ] #88 SOC-04 — Email, calendar, contacts and project actions

## Cross-cutting gates
Identities are never merged from display-name similarity alone, provider visibility/deletion/block semantics propagate, destination account/audience is explicit, and normalized actions never erase important service-specific meaning.

Start by reading child issues #85–#88 to understand the separate feed, ranking, social-write, and email/calendar/contact/project-action scopes. Use the cross-cutting gates in this issue as acceptance criteria: identities must not be merged by display name alone, provider semantics must propagate, destinations and audiences must be explicit, and service-specific meaning must be preserved.

Written by the indexing model from the issue text.