Add P0-6 reference routing gate

[Rimagination]

What changed

• add schema 1.3 task fields and a machine-readable reference_routes.json
• resolve the minimum local references, source IDs, living-source checks, and matched rules in every synthesis route
• add a plan-bound reference_receipt.json contract with file SHA-256, section locators, decision mappings, source versions, milestone checks, and adoption decisions
• keep runner_allowed=false until the receipt passes; make the ordinary R runner require and re-check a passed route contract
• register missing DTA, appraisal, GRADE, PRISMA-DTA, and clubSandwich authority IDs
• document the attestation boundary: the gate verifies the audit record, not comprehension
• update README, SKILL, analysis-plan templates, and the default agent prompt

Why

EasyMeta previously described which references an agent should read, but the prose was not bound to a concrete task or enforced at execution time. That made it possible to route the statistical model correctly while silently skipping, overloading, or using stale methodological guidance.

P0-6 turns reference selection into a deterministic and testable contract from task/domain/stage/data/trigger fields through to runner execution.

Impact

Ordinary run_meta_analysis.R calls now require --route-contract route.json. Existing schema 1.2 plans should be preserved as frozen artifacts and intentionally migrated to schema 1.3.

Validation

• skill-creator quick_validate.py: passed
• P0-1 through P0-6 end-to-end golden/rejection suite: passed
• all 31 P1 medical/ecology scenarios: passed
• black-box subagent routes: diagnostic, raw community matrix, and shared-control dependent effects passed
• adversarial receipt tests: stale living guidance, SHA mismatch, path traversal, missing receipt, and pending runner contract rejected