Directive mining v2 (BLOCKED): community pattern-contribution layer — security redesign required

[Necmttn]

Deferred from #535 and BLOCKED on security redesign (privacy reviewer, see docs/superpowers/specs/2026-06-17-directive-mining-design.md §0.4 / §7). Do NOT build until all blockers resolved:

1. pull_request_target auto-merge feeds 3 code-exec sinks: detector params → SurrealQL on every install (closed typed schema, bound never interpolated); free-text directive/phrasings → stored XSS on the site; validator pwn-request.
2. ">= N contributors" does not stop sybils — content-hash dedup is the sybil counter. Define "independent"; require account history; invert (identical content from many fresh accounts = sybil signal); human gate before graduation.
3. Abstraction leaks — phrasings are raw user turns; per-user contributed/<login>.json deanonymizes.
4. One-time consent + auto-PATCH.

Spec: docs/superpowers/specs/2026-06-17-directive-mining-design.md §0.4, §7.