feat(miner-foundation): version-pin gittensory-engine and wire semver into predicted-gate output

[JSONbored]

Give packages/gittensory-engine a real, checked semver identity that both consumers (the review-stack backend and the future miner) can assert against, so "which engine version produced this verdict" is always answerable — the phase brief calls for extraction "with a version pin." Add an ENGINE_VERSION constant sourced from the package's own package.json at build time (mirroring how packages/gittensory-mcp/bin/gittensory-mcp.js hardcodes packageVersion = "0.6.0" matching its package.json), and surface it on PredictedGateVerdict so any consumer (including the miner's self-review) can log/compare it.

Deliverables

• packages/gittensory-engine/src/version.ts exporting ENGINE_VERSION: string, sourced from (or kept in lockstep with, via a checked test) packages/gittensory-engine/package.json's version field.
• A unit test asserting ENGINE_VERSION === require("../package.json").version so the constant can never silently drift from the published package version (mirrors the version/package.json lockstep pattern implied by gittensory-mcp's hardcoded packageVersion + its own version-audit tooling).
• PredictedGateVerdict (in packages/gittensory-engine/src/predicted-gate.ts) gains an engineVersion: string field populated from ENGINE_VERSION.
• src/rules/predicted-gate.ts's existing test suite is updated to assert the new field is present and non-empty (this IS an allowed test change since it is additive, not weakening).
• packages/gittensory-engine/src/index.ts re-exports ENGINE_VERSION.

References

• packages/gittensory-mcp/bin/gittensory-mcp.js (line 14) — const packageVersion = "0.6.0"; hardcoded-but-package.json-matching version pattern to mirror.
• packages/gittensory-engine/src/predicted-gate.ts — the PredictedGateVerdict type to extend (created by an earlier issue in this phase; must land first).
• Phase brief: "extract reusable deterministic logic ... out of src/ into the new engine package with a version pin."

[linear-code]

JSO-2381