feat: add airdrop implementations

- Add simple-claim: time-locked compressed token distribution
- Add distributor as submodule (merkle-based vesting distributor)

Author: tilo-14

.gitmodules

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+[submodule "airdrop-implementations/distributor"]
+	path = airdrop-implementations/distributor
+	url = https://github.com/Lightprotocol/distributor.git

airdrop-implementations/distributor

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+.anchor
+.cargo
+.DS_Store
+**/.DS_Store
+**/target
+**/*.rs.bk
+node_modules
+test-ledger
+dist
+test-keypair.json

airdrop-implementations/simple-claim/.gitignore

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+# Compressed Claim
+
+Claims time-locked compressed tokens and decompresses them to an SPL token account.
+
+## [README](README.md)
+
+## Source Structure
+
+```text
+program/src/
+├── lib.rs           # entrypoint, declare_id!
+├── error.rs         # ClaimError (3 variants)
+├── instruction.rs   # ClaimIxData, ClaimAccounts, builders
+└── processor.rs     # process_claim logic
+```
+
+## Accounts
+
+### Airdrop PDA
+
+Seeds: `[claimant.to_bytes(), mint.to_bytes(), unlock_slot.to_le_bytes(), bump]`
+
+Derived via `Pubkey::create_program_address`. Holds compressed tokens until claim.
+
+### ClaimIxData (Instruction Data)
+
+| Field | Type | Description |
+|-------|------|-------------|
+| proof | ValidityProof | ZK proof for compressed account |
+| packed_tree_info | PackedStateTreeInfo | Merkle tree state info |
+| amount | u64 | Tokens to claim |
+| lamports | Option<u64> | Optional lamports to transfer |
+| mint | Pubkey | Token mint address |
+| unlock_slot | u64 | Slot when tokens unlock |
+| bump_seed | u8 | PDA bump seed |
+
+## Instructions
+
+| Instruction | Path | Accounts | Logic |
+|-------------|------|----------|-------|
+| Claim | processor.rs | claimant (signer), fee_payer (signer), airdrop_pda, + 13 Light/CToken accounts | Verifies unlock_slot <= current_slot, validates PDA, invokes decompress CPI |
+
+### Claim Accounts (16 total)
+
+0. claimant (signer)
+1. fee_payer (signer)
+2. associated_airdrop_pda
+3. ctoken_cpi_authority_pda
+4. light_system_program
+5. registered_program_pda
+6. noop_program
+7. account_compression_authority
+8. account_compression_program
+9. ctoken_program
+10. spl_interface_pda (token_pool)
+11. decompress_destination (writable)
+12. token_program
+13. system_program
+14. state_tree (writable)
+15. queue (writable)
+
+## Key Concepts
+
+**Time-lock**: Tokens unlock at `unlock_slot`. Claim fails if `current_slot < unlock_slot`.
+
+**PDA Derivation**: `[claimant, mint, unlock_slot, bump]` - ensures only rightful claimant can claim.
+
+**Decompress CPI**: Invokes `light_ctoken_sdk::decompress` to convert compressed tokens to SPL.
+
+## Security
+
+**Signer checks**: Both claimant and fee_payer must sign.
+
+**PDA validation**: Derived PDA must match provided airdrop_pda account.
+
+**Program check**: ctoken_program must equal `light_ctoken_sdk::ctoken::id()`.
+
+## Errors
+
+| Error | Description |
+|-------|-------------|
+| MissingRequiredSignature | Claimant or fee_payer not signer |
+| TokensLocked | current_slot < unlock_slot |
+| InvalidPDA | Derived PDA doesn't match provided account |