feat: multi-asset deposit support via shared allowlist [NF-05]

[AbdulmujibOladayo]

Summary

Wires shared::allowlist into VaultRouter as a deposit-asset registry, enabling multi-asset deposits (e.g. USDC + EURC) while keeping per-asset balances independent.

Changes

contracts/vault_router/Cargo.toml

• Added shared = { path = "../shared" } dependency

contracts/vault_router/src/error.rs

• Added AssetNotAllowed = 4

contracts/vault_router/src/lib.rs

• initialize() now takes initial_assets: Vec<Address> and calls shared::allowlist::init_allowlist()
• deposit(user, tier, asset, amount) — validates asset against the allowlist before forwarding; rejects with AssetNotAllowed for unlisted assets
• withdraw(user, tier, asset) and early_exit(user, tier, asset) — asset-aware pass-through
• add_deposit_asset(admin, asset) / remove_deposit_asset(admin, asset) — admin-gated allowlist management
• is_deposit_asset_allowed(asset) -> bool — read-only query
• position(user, tier, asset) — per-asset position query

Tests

• test_allowed_asset_deposit_succeeds
• test_non_allowed_asset_deposit_rejected (#[should_panic])
• test_add_then_deposit_second_asset — adds EURC, verifies deposit succeeds
• test_remove_asset_blocks_future_deposits
• test_per_asset_position_is_independent — USDC and EURC positions are independent
• Below-min-deposit guards for Flex and L12
• Double-initialize guard

Acceptance Criteria

• shared::allowlist is now imported and has active call sites
• Non-allowlisted asset deposit rejected with AssetNotAllowed
• Per-asset positions queried independently
• Existing USDC path unchanged (USDC passed as initial_assets in initialize)

closes #80

[vercel]

@AbdulmujibOladayo is attempting to deploy a commit to the wumibals' projects Team on Vercel.

A member of the Team first needs to authorize it.

[wumibals]

LGTM

[wumibals]

outstanding work