feat: compose decisions and support project packs

[bearmug]

Summary

• add jev decide composition with gate exit semantics and decision-only output
• support explicit project-owned --pack-file for ask/gate/decide
• add correlated run/decision IDs and optional JSONL record sink
• include offline tools in the published tarball and document installed workflows
• bump package to 0.2.0

Verification

• npm run build
• npm test (93 passing)
• npm run test:integration (10 passing)
• npm pack smoke: dist/commands/decide.js and tools/evaluate.mjs included
• offline stub smoke: decide with bundled and explicit pack-file

After merge, publish release tag v0.2.0; the npm workflow stages the package for manual approval.