Gated mint program

[pileks]

Introduces gated_mint, a new program that gates an SPL Mint behind an admin-managed whitelist by holding the mint's freeze authority. Whitelisted users move tokens through gated_invoke, which thaws relevant token accounts before a CPI into a whitelisted target program and re-freezes them after. Couples into v08_launchpad: any base mint with a freeze authority must point it at the deterministic gated_mint_config PDA.

This PR stacks on pileks/launchpad-v8; the launchpad_v8 program/SDK/tests are part of this diff against develop but land via that PR. The net new scope here is the gated_mint program, its SDK module, its tests, and the 19-line freeze-authority check in initialize_launch.

Instructions

Instruction	Role
initialize_gated_mint	Moves the mint's freeze authority into the gated_mint_config PDA (seed ["gated_mint_config", mint]) via set_authority CPI; stores per-mint admin.
add_whitelisted_user	Admin-gated; creates a WhitelistedUser PDA at ["whitelisted_user", mint, user].
gated_invoke	Whitelisted-user-only; for each mint token account in remaining_accounts, thaws if frozen, runs invoke on target_program (must be in WHITELISTED_PROGRAMS, must not be gated_mint::ID), then re-freezes any account left in Initialized state.
disable_gating	Admin-only one-way switch; blocks gated_invoke and add_whitelisted_user, unlocks permissionless thaw_account.
thaw_account	Permissionless unwind path callable only after disable_gating; thaws a single token account of the gated mint.

Other Changes

• v08_launchpad::initialize_launch now requires that, if base_mint.freeze_authority is set, it equals the canonical gated_mint_config PDA derived from base_mint. This is a pure on-chain find_program_address check, no CPI into gated_mint. Mints without a freeze authority continue to work unchanged.
• SDK: new @metadaoproject/programs/gated_mint (v0.1) module with GatedMintClient, PDA helpers, and generated types; re-exported from the package root.
• Tests: unit tests for each gated_mint instruction plus tests/integration/gatedLaunchpadV8.test.ts exercising the full lifecycle: init gated mint → init/start/fund/settle launchpad_v8 launch → claim (frozen ATAs thawed and re-frozen via gated_invoke) → disable gating → permissionless thaw_account.