Knowledge wiki: add claims array to concept, entity, and synthesis types

[mindsocket]

Context

From the memory-wiki comparison (issue #100). Claims are structured sub-page beliefs — an assertion with optional evidence, confidence, and lifecycle status. Adding them to the knowledge wiki schema brings machine-queryable belief tracking at finer granularity than a page, without requiring the full memory-wiki toolchain.

Decision: add claims as an optional field on concept, entity, and synthesis (not source, note, or index).

Schema shape

Each claim:

{
  "id": "claim.alpha.main",       // optional stable identifier
  "text": "The assertion",         // required
  "status": "supported",           // supported | contested | contradicted | superseded
  "confidence": 0.9,               // 0–1
  "evidence": [
    {
      "sourceId": "source.alpha",  // ID or wikilink of source page
      "path": "experiments/run-3", // optional path within source
      "lines": "42-67",            // optional line range
      "weight": 0.9,               // 0–1
      "note": "Primary experiment" // optional free-text
    }
  ]
}

The claims property should be an optional array on concept, entity, and synthesis $defs in schemas/_knowledge_wiki.json. The claim and evidence item shapes should be defined as $defs in the partial for reuse.

Rules to add

Add to the rules array in _knowledge_wiki.json:

• claim-without-evidence (category: coherence) — flags any page where a claim exists with no evidence entries. Should only trigger if claims is present. Message should name the claim id or text.
• contested-claim (category: coherence) — flags any page where a claim has status of contested or contradicted. Surfaces pages with active epistemic conflict for review.

Both rules are optional-field-aware: they only run when claims is present, so pages without the field are unaffected.

Acceptance criteria

• claims array accepted and validated on concept, entity, synthesis; rejected on source, note, index
• Both rules fire correctly in tests and are silent on pages without claims
• Schema $defs for claim and evidence item shapes are reusable (referenced by all three types)

Reference

docs/memory-wiki-research.md — "Claims model" section and note; "What's worth adopting → Claims" section