Add proactive commit suggestions

[Tunde-cs]

Summary

Adds proactive follow-up suggestions to engram_commit responses.

After a successful commit, Engram now returns up to two related facts the agent may also want to commit, making the system more proactive instead of purely reactive.

What changed

• added lightweight post-commit suggestion generation in EngramEngine
• returned suggestions in commit responses
• kept duplicate, delete, and no-op commit responses consistent with suggestions: []
• updated the engram_commit return contract docstring to include suggestions
• added focused engine tests for proactive suggestions and response shape

Why

This helps agents preserve more complete knowledge in a single pass. For example, after committing a rate limit, Engram can suggest also committing the retry strategy or circuit breaker threshold.

Validation

• pytest -q tests/test_engine.py
• ruff check .
• manually verified /api/commit returns suggestions for a new rate-limit fact

[vercel]

@Tunde-cs is attempting to deploy a commit to the agentscreator's projects Team on Vercel.

A member of the Team first needs to authorize it.