feat(amm): apply trading fees to LP accounting

[3esmit]

Purpose

Build on the #20 stage-1 fee-tier work by applying trading fees to swap and liquidity accounting so LPs earn and realize fees through normal AMM usage.
Closes #19

What Changed

• Cherry-picked the surplus-removal fix from feat: enhance remove liquidity function to handle surplus balances #16 so this branch includes the live-vault withdrawal behavior required for LP fee realization.
• Applied fee-aware swap pricing using the pool's configured fee tier while continuing to transfer the full input amount into the vault.
• Updated tracked reserves with the fee-adjusted input amount so the charged fee remains in the vault as LP-owned surplus.
• Updated add_liquidity to mint LP against live vault balances when surplus exists, preventing new LPs from receiving fees accrued before they joined.
• Kept remove_liquidity reserve accounting intact while distributing proportional live vault balances, allowing withdrawing LPs to realize accrued trading fees.
• Added AMM unit and integration coverage for fee rounding edge cases, repeated swaps, fee payout on liquidity removal, and add-liquidity behavior after fees accrue.

Review Focus

• Confirm the cherry-picked surplus-removal change from fix/remove-lp-surplus-missing is the intended base for this PR.
• Swap reserve updates now intentionally differ from vault balance changes by the configured fee amount.
• Live vault balances now affect LP minting when surplus exists.
• Liquidity removal should pay out accumulated surplus proportionally without mutating tracked reserves incorrectly.
• Multi-transaction integration scenarios now rely on current account nonces as fees accumulate across sequential operations.

How To Test

1. cargo +nightly fmt --all -- --check
2. taplo fmt --check .
3. RISC0_SKIP_BUILD=1 cargo +1.94.0 clippy --workspace --all-targets -- -D warnings
4. RISC0_DEV_MODE=1 cargo +1.94.0 test --workspace --exclude integration_tests
5. RISC0_DEV_MODE=1 cargo +1.94.0 test -p integration_tests

[Copilot]

Pull request overview

Implements LP-trading-fee accrual and realization for the AMM by applying a configured fee tier to swap pricing while keeping the fee portion as vault surplus, and by adjusting liquidity add/remove accounting so LPs realize fees via normal AMM flows.

Changes:

• Adds fee-tier plumbing and validation (core constants/helpers, NewDefinition instruction/IDL, guest entrypoint, and runtime asserts in add/swap/remove).
• Applies fee-aware swap reserve accounting (full input deposited to vault, fee-adjusted amount applied to reserves) and preserves fee surplus during add/remove liquidity.
• Expands unit + integration tests for fee tiers, fee rounding edge cases, multi-swap accumulation, and surplus payout behavior.

Reviewed changes

Copilot reviewed 8 out of 9 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
integration_tests/tests/amm.rs	Updates integration scenarios to use fee tiers, current nonces, and adds multi-swap + add/remove-after-fee tests.
amm/src/tests.rs	Extends unit tests for fee tiers, swap rounding edge cases, add-liquidity with surplus, and remove-liquidity vault/reserve mismatch checks.
amm/src/swap.rs	Applies fee tier to swap pricing and updates tracked reserves using fee-adjusted input.
amm/src/remove.rs	Computes withdraw payouts from live vault balances (including surplus) while updating tracked reserves from reserve amounts.
amm/src/new_definition.rs	Adds fees parameter, validates supported tiers, and stores the chosen tier in PoolDefinition.
amm/src/add.rs	Quotes/mints LP against live vault balances to avoid diluting pre-existing fee surplus.
amm/methods/guest/src/bin/amm.rs	Wires fees through the guest entrypoint for pool creation.
amm/core/src/lib.rs	Adds fee tier constants + validation helpers, and extends the instruction schema and PoolDefinition docs.
amm/amm-idl.json	Extends the NewDefinition IDL to include the fees field.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

Pull request overview

Copilot reviewed 8 out of 9 changed files in this pull request and generated no new comments.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[3esmit]

To review the changes regarding only the apply of fee on the swaps, see the commit 695b032 changes, otherwise you would also see the changes of the dependent PRs (remove lp fix, and fee setup):

[0x-r4bbit]

@3esmit I've rebased the work in #46 and updated the changes, such that fees accumulate in the reserves (no surplus).

Please take a look.
Will close this one in favour of #46