Website/transactions: add links to actual files and methods

Author: dannywillems

website/docs/developers/transactions.md

@@ -63,7 +63,7 @@ The first pass validates preconditions and begins transaction application:
 - Returns `TransactionPartiallyApplied` containing transaction state
 
 **Function:**
-`ledger/src/scan_state/transaction_logic/transaction_partially_applied.rs`
+[`ledger/src/scan_state/transaction_logic/transaction_partially_applied.rs`](https://github.com/o1-labs/mina-rust/blob/develop/ledger/src/scan_state/transaction_logic/transaction_partially_applied.rs#L190)
 
 ### Second Pass (apply_transaction_second_pass)
 
@@ -74,28 +74,28 @@ The second pass completes the transaction after SNARK work:
 - Updates receipt chain hashes
 - Returns final `TransactionApplied` status
 
-**Function:** `ledger/src/scan_state/transaction_logic/transaction_applied.rs`
+**Function:**
+[`ledger/src/scan_state/transaction_logic/transaction_applied.rs`](https://github.com/o1-labs/mina-rust/blob/develop/ledger/src/scan_state/transaction_logic/transaction_applied.rs)
 
 ## Common Transaction Components
 
 ### Fees
 
-All user-initiated transactions require fees:
-
-```rust
-pub struct Fee(Amount);
-```
+All user-initiated transactions require fees. The `Fee` type is generated by a
+macro along with other currency types in
+[`ledger/src/scan_state/currency.rs`](https://github.com/o1-labs/mina-rust/blob/develop/ledger/src/scan_state/currency.rs#L575-L578).
 
-Fees are paid by the transaction sender (or fee payer in zkApp commands) and
-distributed to block producers through fee transfers.
+Fees serve two purposes: they compensate block producers for including
+transactions and prevent network spam by making it economically infeasible to
+flood the network with transactions. Fees are paid by the transaction sender (or
+fee payer in zkApp commands) and distributed to block producers through fee
+transfers.
 
 ### Nonces
 
-User accounts maintain nonces to prevent replay attacks:
-
-```rust
-pub struct Nonce(u32);
-```
+User accounts maintain nonces to prevent replay attacks. The `Nonce` type is
+generated by a macro along with other currency types in
+[`ledger/src/scan_state/currency.rs`](https://github.com/o1-labs/mina-rust/blob/develop/ledger/src/scan_state/currency.rs#L575-L578).
 
 Each user-initiated transaction must specify the correct nonce, which increments
 after successful application.
@@ -104,21 +104,23 @@ after successful application.
 
 Transactions can include optional 32-byte memos:
 
-```rust
-pub struct Memo {
-    data: [u8; MEMO_BYTES],
-}
+<!-- CODE_REFERENCE: ledger/src/scan_state/transaction_logic/mod.rs#L548-L548 -->
+
+```rust reference title="ledger/src/scan_state/transaction_logic/mod.rs"
+https://github.com/o1-labs/mina-rust/blob/develop/ledger/src/scan_state/transaction_logic/mod.rs#L548-L548
 ```
 
 Memos provide auxiliary information and are included in transaction commitments.
 
 ### Slots
 
-Transactions include validity windows using slot numbers:
+A slot is a fixed time interval in the consensus protocol during which a block
+can be produced. Slots are used to measure time in the blockchain and determine
+block production opportunities.
 
-```rust
-pub struct Slot(u32);
-```
+Transactions include validity windows using slot numbers. The `Slot` type is
+generated by a macro along with other currency types in
+[`ledger/src/scan_state/currency.rs`](https://github.com/o1-labs/mina-rust/blob/develop/ledger/src/scan_state/currency.rs#L575-L578).
 
 The `valid_until` field specifies when a transaction expires.
 
@@ -156,11 +158,16 @@ fee payer failures).
 
 Comprehensive tests for each transaction type verify correct ledger updates:
 
-- `tests/test_transaction_logic_first_pass.rs` - Payment transactions
-- `tests/test_transaction_logic_first_pass_delegation.rs` - Stake delegations
-- `tests/test_transaction_logic_first_pass_fee_transfer.rs` - Fee transfers
-- `tests/test_transaction_logic_first_pass_coinbase.rs` - Coinbase rewards
-- `tests/test_transaction_logic_first_pass_zkapp.rs` - zkApp commands
+- [`ledger/tests/test_transaction_logic_first_pass.rs`](https://github.com/o1-labs/mina-rust/blob/develop/ledger/tests/test_transaction_logic_first_pass.rs) -
+  Payment transactions
+- [`ledger/tests/test_transaction_logic_first_pass_delegation.rs`](https://github.com/o1-labs/mina-rust/blob/develop/ledger/tests/test_transaction_logic_first_pass_delegation.rs) -
+  Stake delegations
+- [`ledger/tests/test_transaction_logic_first_pass_fee_transfer.rs`](https://github.com/o1-labs/mina-rust/blob/develop/ledger/tests/test_transaction_logic_first_pass_fee_transfer.rs) -
+  Fee transfers
+- [`ledger/tests/test_transaction_logic_first_pass_coinbase.rs`](https://github.com/o1-labs/mina-rust/blob/develop/ledger/tests/test_transaction_logic_first_pass_coinbase.rs) -
+  Coinbase rewards
+- [`ledger/tests/test_transaction_logic_first_pass_zkapp.rs`](https://github.com/o1-labs/mina-rust/blob/develop/ledger/tests/test_transaction_logic_first_pass_zkapp.rs) -
+  zkApp commands
 
 ## Further Reading
 
@@ -174,13 +181,15 @@ Comprehensive tests for each transaction type verify correct ledger updates:
 
 ## Related Files
 
-- `ledger/src/scan_state/transaction_logic/mod.rs` - Transaction type
-  definitions
-- `ledger/src/scan_state/transaction_logic/transaction_partially_applied.rs` -
+- [`ledger/src/scan_state/transaction_logic/mod.rs`](https://github.com/o1-labs/mina-rust/blob/develop/ledger/src/scan_state/transaction_logic/mod.rs) -
+  Transaction type definitions
+- [`ledger/src/scan_state/transaction_logic/transaction_partially_applied.rs`](https://github.com/o1-labs/mina-rust/blob/develop/ledger/src/scan_state/transaction_logic/transaction_partially_applied.rs) -
   First pass application
-- `ledger/src/scan_state/transaction_logic/transaction_applied.rs` - Second pass
-  application
-- `ledger/src/scan_state/transaction_logic/signed_command.rs` - Signed command
-  types
-- `ledger/src/scan_state/transaction_logic/zkapp_command/` - zkApp command
-  implementation
+- [`ledger/src/scan_state/transaction_logic/transaction_applied.rs`](https://github.com/o1-labs/mina-rust/blob/develop/ledger/src/scan_state/transaction_logic/transaction_applied.rs) -
+  Second pass application
+- [`ledger/src/scan_state/transaction_logic/signed_command.rs`](https://github.com/o1-labs/mina-rust/blob/develop/ledger/src/scan_state/transaction_logic/signed_command.rs) -
+  Signed command types
+- [`ledger/src/scan_state/transaction_logic/zkapp_command/`](https://github.com/o1-labs/mina-rust/tree/develop/ledger/src/scan_state/transaction_logic/zkapp_command) -
+  zkApp command implementation
+- [`ledger/src/scan_state/currency.rs`](https://github.com/o1-labs/mina-rust/blob/develop/ledger/src/scan_state/currency.rs) -
+  Currency types (Fee, Nonce, Slot, Amount, Balance)