roadmap(pillar 1): anti-slop contribution quality layer

[JSONbored]

Parent roadmap: #525

Goal

One deterministic "slop" core, consumed by both products. It never reads source; it scores diff metadata both sides already produce, and supplies the gittensor rubric the miner's own harness applies to the actual code. This closes the slop gap on supply (miners submit real work) and demand (maintainers enforce quality).

Children

• feat(signals): deterministic slop-assessment core #530 — deterministic slop-assessment core
• feat(mcp): gittensory_check_slop_risk tool + real-vs-slop rubric #531 — gittensory_check_slop_risk tool + rubric
• feat(github-app): slop gate mode + check surfacing #532 — slop gate mode + check surfacing
• feat(github-app): issue-side slop triage #533 — issue-side slop triage

Done when

• buildSlopAssessment is pure/deterministic and reused by both the miner MCP tool and the maintainer CI.
• Miners get actionable slop reasons + the rubric pre-submit; maintainers get an opt-in slop gate that defaults to advisory.

Cross-cutting acceptance criteria

Inherits the wave criteria (#525): npm run test:ci, 97%+ coverage, public/private output boundary, advisory-by-default, no source upload.