[P2][RES-03] Living articles and research artifacts

Programme: #1
Epic: #25

## Objective
Turn research into durable, evidence-backed synthesized publications that can evolve as sources change without masquerading as original publisher pages.

## Scope
- Article/research artifact schema with claim/evidence graph, source list, publication/observation dates and unresolved gaps.
- User-selectable depth/format and section organization.
- Inline provenance/contradiction/uncertainty controls.
- Revision history, diff, annotations, pin/lock and reviewable updates.
- Export/share with source-aware quotation/caching constraints.
- Change notifications driven by source dependency invalidation.
- Original-source navigation from claims/passages.

## Product rules
- Generated publication is clearly labeled synthesis.
- Material factual/purchase-critical claims require evidence or explicit uncertainty.
- New source data proposes/creates a revision; it does not silently rewrite text being read.

## Acceptance criteria
- [ ] Every material claim links to evidence or is explicitly marked unresolved/inferred.
- [ ] Contradictions remain visible in the synthesized artifact.
- [ ] Source updates create reviewable revisions with meaningful diffs.
- [ ] User annotations survive regenerated revisions where anchors remain valid or are surfaced for repair.
- [ ] Export respects source access/quotation/redaction policy.
- [ ] User can open originals from the relevant claim/evidence context.

## Dependencies
- RES-02
- UI-02

**First phase:** P2
**Maturity target:** P5
**Owner:** connectors-domains

No files, tests, or entry points are named. Start by reading this issue alongside dependencies RES-02 and UI-02, then identify the existing artifact and source-update flows before defining an implementation plan. Done means all listed acceptance criteria are addressed, including evidence links, visible contradictions, reviewable revisions, annotation handling, export policy, and original-source navigation.

Written by the indexing model from the issue text.