Add AgentEscrow genesis migration plan

[wallaceyap91-sys]

Summary

• Add docs/agent-escrow-genesis-migration.md for issue AgentEscrow genesis state migration plan + testnet cutover smoke tests #86
• Document the candidate genesis address, zero-state invariants, cutover phases, smoke-test matrix, Council-owned upgrade path, and public RFC checklist
• Keep this PR docs-only so the migration plan can be reviewed before implementing test/genesis_cutover.t.sol

Fixes #86

Verification

• Checked markdown structure and key acceptance-criteria terms locally
• Confirmed the document is ASCII-only
• Confirmed the uploaded fork file matches the locally reviewed document

[abhicris]

Welcome to kcolbchain, @wallaceyap91-sys — glad you're here. 🌱

Here's what happens from this PR:

1. Our automated review looks for obvious issues (tests, secrets, size) within a couple of hours.
2. If it's clean and CI passes, we merge without back-and-forth.
3. If we need changes, we'll leave a specific comment — not a generic nit. Push another commit and we re-review.

While you wait:

• Run the repo's tests locally (see the repo README.md).
• Keep the PR scoped to one concern — bigger PRs land slower.
• Don't commit tokens or .env contents.

What happens after your first merge

• You're listed on https://kcolbchain.com/contributors/ (opt-out anytime via data/contributors-optout.txt).
• At 2+ merged PRs you're a Regular; at 5+ you're a Fellow — Fellows are the pool we invite first for paid research, partner-org gigs, and grant-funded work. Details: https://kcolbchain.com/docs/org-contribution-policy.html
• Looking for what to pick up next? https://kcolbchain.com/invitations/ lists open help-wanted / good-first-issue across every kcolbchain repo.

Thanks for writing the code. We're building this to last.

[wallaceyap91-sys]

Added test/genesis_cutover.t.sol so the PR now includes the smoke-test corpus described in the migration plan:

• runtime-code parity between the genesis-style deployment and a fresh deployment
• Council owner, zero-balance, no-payment, chain id, and aggregator genesis invariants
• post-genesis happy path, timeout refund, challenge-period gating, ownership transfer, and request-id domain separation

I could not run Forge locally on this Windows host because Foundry is not installed, so this is submitted as a compile-oriented smoke-test pass for CI/review.