Custom AST-grep deterministic rule layer

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Phase 3 — Analysis depth, analytics & developer experience

Context

Operators want repo-specific structural rules enforced deterministically, groundably, and cheaply (no AI cost).

Goal

A config-driven AST-grep rule layer feeding review findings.

Requirements

• review.ast_rules (rule dirs / inline rules) run over changed files (ideally inside the enrichment service from the tool-runner work); matches become normalized findings (advisory, or blocking if configured) and ground the AI.
• Deterministic + bounded; default-OFF; org-shareable via the review.shared_config knob.

Deliverables

• AST-grep runner + rule loading + finding mapping + tests + docs.

Expected outcome

• Enforce house patterns deterministically at zero AI cost; fewer style debates.

Effort

L.

[linear-code]

JSO-2046

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2026-07-01 issue audit: Consolidating into REES epic #1499 — AST-grep is the structural-analyzer continuation of the same runtime (alongside #1509/#1510).