feat(unlock-app): expose discount codes for paid locks

[wilber123451-design]

Summary

• add a dedicated Discount Codes settings tab for paid locks
• reuse the existing capped promo-code hook and enable it on first save
• keep free locks on the existing settings list and disable mutations for non-managers
• handle unsupported PublicLock versions and networks with explicit states

Prior work

This revives the approach from #16409 by @Zaid-L9 against current master. That author is credited as a co-author. This version adds read-only handling for non-managers, stricter paid-lock detection, broader tab tests, and omits unrelated changes from the prior diff.

Testing

• node .yarn/releases/yarn-4.10.3.cjs workspace @unlock-protocol/unlock-app vitest run src/__tests__/components/interface/locks/Settings/settingsTabs.test.ts --environment=jsdom (3 tests passed)
• node .yarn/releases/yarn-4.10.3.cjs workspace @unlock-protocol/unlock-app eslint <touched files> (0 errors)
• git diff --check

CLA registration: #16579

Base USDC payout address: 0xd3CE8223E6b0F446a887953aF623B9c72233Ba39

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