[Pepps233]

Summary

Evolution jobs now freeze their evidence and configuration inputs, persist immutable stage artifacts, and resume from durable checkpoints without duplicating writes or harness activation.

Reasoning

A manifest-first state machine with fenced leases keeps recovery deterministic across process exits and concurrent Diffex processes.

Content-addressed artifacts and stable idempotency keys separate immutable stage output from mutable job progress.

The reserved counter-slot remains disabled so this PR does not implement later Counter behavior.

Changes

• Adds explicit job stages, terminal outcomes, machine-readable failure reasons, frozen snapshot metadata, and committed processed-evidence cursors.
• Adds content-addressed filesystem persistence, compare-and-swap manifests, append-only ledger events, scope leases with heartbeats, stale-worker fencing, and one global writer lock.
• Adds deterministic automatic and manual trigger policy, including the strict token threshold, settled-invocation minimum, cooldown, no-evidence response, and overlap blocking.
• Makes the evolution pipeline stage-oriented with idempotent model, write, and activation calls.
• Adds a bounded process-neutral background worker with cancellation, retry backoff, and an interactive-priority gate.
• Adds explicit retention and recovery policy without adding later roadmap behavior.

Testing

• npm run check
• node ../../node_modules/vitest/dist/cli.js --run test/contracts.test.ts test/control-plane.test.ts test/filesystem-store.test.ts test/worker.test.ts from packages/evolution
• ./test.sh