Fix metadata MetadataPointerInstruction: use OptionalNonZeroPubkey (66 bytes)

token-2022-v7.0.0 uses OptionalNonZeroPubkey (32-byte raw pubkey, not
COption/PodCOption flags) for both authority and metadata_address fields.
Correct format: [39, 0, authority(32), metadata_address(32)] = 66 bytes.

Previous attempts with 68 bytes (1-byte flags) and 74 bytes (4-byte
PodCOption flags) both fail because the struct expects exactly 64 bytes
of payload after the 2-byte header.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: mikemaccana

tokens/token-2022/metadata/quasar/src/lib.rs

@@ -99,17 +99,13 @@ pub fn handle_initialize(
         .invoke()?;
 
     // InitializeMetadataPointer: opcode 39, sub-opcode 0.
-    // Uses PodCOption<Pubkey> encoding: 4-byte LE flag + 32-byte pubkey = 36 bytes each.
-    // Layout: [39, 0, 1,0,0,0, authority(32), 1,0,0,0, metadata_address(32)] = 74 bytes
-    let mut mp_data = [0u8; 74];
+    // Uses OptionalNonZeroPubkey (32 bytes each, all-zeros = None).
+    // Layout: [39, 0, authority(32), metadata_address(32)] = 66 bytes
+    let mut mp_data = [0u8; 66];
     mp_data[0] = 39;
     mp_data[1] = 0;
-    mp_data[2] = 1; // PodCOption::Some flag (4-byte LE: [1,0,0,0])
-    // mp_data[3..6] already zero
-    mp_data[6..38].copy_from_slice(accounts.payer.to_account_view().address().as_ref());
-    mp_data[38] = 1; // PodCOption::Some flag (4-byte LE: [1,0,0,0])
-    // mp_data[39..42] already zero
-    mp_data[42..74]
+    mp_data[2..34].copy_from_slice(accounts.payer.to_account_view().address().as_ref());
+    mp_data[34..66]
         .copy_from_slice(accounts.mint_account.to_account_view().address().as_ref());
 
     CpiCall::new(