Staking | Allow everyone to delegate stake

[lucasrparfin]

Open up Public Chain staking to non-whitelisted users (per-validator whitelisting)

Context

Staking on the Public Chain is currently restricted to a whitelist, with whitelisted stakers earning 55% APY. We want to open staking to everyone else at a lower, defined APY.

With the Nimofast vault project shelved and nothing else currently active on the Public Chain, opening up staking has increased in priority (it was previously deprioritised in the context of having a vault).

Two approaches were discussed:

1. Tier-based APY logic (existing PR — [axyl-private#673](https://github.com/raylsnetwork/axyl-private/pull/673), from issue [#599](https://github.com/raylsnetwork/axyl-private/issues/599)): opens staking to more stakers with a different APY, but requires implementing checks/lists of who can stake where. It touches APY logic and doesn't work out of the box.
2. Per-validator whitelisting (decided approach): don't touch APY logic for now. Manage whitelisting at the validator level and spin up a new validator with the whitelist disabled and a high commission.

Decision: go with the per-validator approach. It's more flexible, keeps APY logic untouched, and makes future changes (e.g. moving to 2+ explicit tiers) easier if needed.

Goal

Enable open (non-whitelisted) staking on the Public Chain by launching a new validator, while keeping the existing whitelisted staking (55% APY) unchanged.

Approach

• Support enabling/disabling the whitelist per validator.
• Launch a new validator with:
  • Whitelist disabled (open to all delegators).
  • A high commission (e.g. 35%), so delegators effectively earn ~20% APY.
• Keep existing whitelisted validator(s) untouched → whitelisted users continue earning 55% APY.
• Do not change the APY logic for now.

Acceptance criteria

• Whitelisting can be managed (enabled/disabled) on a per-validator basis.
• Existing whitelisted users continue earning 55% APY on the existing validator(s).
• A new open validator (whitelist disabled, ~35% commission) allows anyone to stake and earn ~20% APY.
• APY logic is left unchanged.
• Tested on testnet before going live.

To scope / open questions

• Confirm final commission rate and resulting delegator APY (35% commission → ~20% — to validate).
• Effort estimate and feasibility of the per-validator whitelist toggle (needs check from Meglena).
• Path for a user staking on the open validator to later become eligible for whitelisted staking (they'd re-delegate to the whitelisted validator once whitelisted — confirm this covers Alex's requirement chore(deps)(deps): bump thin-vec from 0.2.14 to 0.2.18 #1).
• Behavior if whitelisting is disabled on the whitelisted validator (all users effectively fall into the open tier — confirm this covers requirement chore(deps)(deps): bump rpassword from 7.4.0 to 7.5.0 #2).
• Testnet test plan and sign-off owner.

Slack thread

• https://parfin.slack.com/archives/C0B98RQEDCJ/p1785253927794209