P3 tokenomics: token utility, emission schedule, supply policy, treasury (P3-5.1/5.2)

[umeradl]

Part of the P3 mechanism-design push (#36).

Summary

Turn DIN from a devnet utility/staking token into a credible protocol asset. Today DinToken mints only via DinCoordinator.depositAndMint (fixed dinPerEth rate, owner-withdrawable ETH, no cap, no burn, no emission, no treasury).

Scope (from MECHANISM_DESIGN §7)

• Utility / demand sinks: staking (primary), DIN-denominated fees, reward-pool deposits, governance weight (P5+ hook only)
• Emission contract (P3-5.2): per-GI reward subsidy on a diminishing schedule — ✅ geometric decay per epoch confirmed, GI-lifecycle-tied inflation guard confirmed. MAX_SUPPLY: ✅ resolved as deliberately open/dynamic for now, not a hard cap at freeze time (supply governed by issuance vs. burn; hard cap possible later via governance)
• depositAndMint: effectively an unlimited mint at an admin-set rate — ✅ Resolved: keep active (faucet mode) on DevNet; cap on testnet; retire on mainnet, replaced by either a proper on-ramp/ICO or a validator-airdrop program rewarding testnet participants — both kept open, final model TBD; route deposited ETH backing to treasury instead of owner() withdrawal
• Burn sinks: ✅ Resolved: explicit 50% slashed-stake burn share; fee-burn fraction from both on-chain protocol fees and validator network fees (dual sources), start at 0%, keep the hook
• Treasury: dedicated address/contract receiving network fee split, slashed-stake share, deposit backing; DAO-controlled spend
• Modelling before contracts (P3-5.2): simulate whether pool + emission produce stable validator income at target / 10× / 0.1× participation — wrong answers are expensive post-audit

Open decisions (→ tokenomics discussion)

• Emission schedule shape and MAX_SUPPLY (MECHANISM_DESIGN §9, decision 5) — ✅ partially resolved, see above
• Reward split percentages (decision 3, simulated in P3-5.2) — still open, not addressed
• depositAndMint cap/retirement plan (decision 8 — flag before audit) — ✅ resolved, see above

Status (2026-07-21): the above resolutions are from Abraham (CEO, white-paper author) via Slack; recorded in MECHANISM_DESIGN.md §9 and tokenomics-design.md §6. Note the fee-denomination recommendation elsewhere in this doc's sibling issue (#43) is also revised — see there.

Design sources

MECHANISM_DESIGN §7 · issues/tokenomics.md · whitepaper-summary §5, §8 gap item 8 (white paper: Eth2-style decreasing inflation + fee-funded burn)

Roadmap anchors: P3-5.1 (token utility design), P3-5.2 (emission & distribution model), P3-DOC5 (tokenomics paper)