chore: add helper examples to calculate program PDAs

These is needed because SPEL currently doesn't support PDA calculation
the way our programs do (we wrap our seeds in SHA256)

programs/ata/examples/ata_pdas.rs

@@ -0,0 +1,61 @@
+//! Print the Associated Token Account (ATA) address for an owner + token definition.
+//!
+//! Usage:
+//!   cargo run -q -p ata_program --example ata_pdas -- <ata_pid> <token_pid> <owner> <definition>
+//!
+//! `*_pid` are ProgramIds as 8 comma-separated u32 limbs (as printed by `spel program-id`);
+//! `owner` and `definition` are base58 account ids.
+
+use std::str::FromStr;
+
+use ata_core::{compute_ata_seed, get_associated_token_account_id};
+use nssa_core::{account::AccountId, program::ProgramId};
+
+// Accepts a ProgramId as 8 comma-separated u32 limbs, a 64-char ImageID hex, or a base58
+// ImageID. Hex/base58 are decoded as the 32 ImageID bytes read little-endian per u32 word,
+// matching how `spel program-id` maps the ImageID to limbs.
+fn parse_pid(s: &str) -> ProgramId {
+    if s.contains(',') {
+        let limbs: Vec<u32> = s
+            .split(',')
+            .map(|x| x.trim().parse().expect("ProgramId limb must be a u32"))
+            .collect();
+        assert_eq!(limbs.len(), 8, "ProgramId must be 8 u32 limbs");
+        let mut pid: ProgramId = [0u32; 8];
+        pid.copy_from_slice(&limbs);
+        return pid;
+    }
+    let bytes: [u8; 32] = if s.len() == 64 && s.bytes().all(|b| b.is_ascii_hexdigit()) {
+        let mut out = [0u8; 32];
+        for (byte, pair) in out.iter_mut().zip(s.as_bytes().chunks_exact(2)) {
+            let pair: [u8; 2] = pair.try_into().expect("hex pair");
+            let hex = std::str::from_utf8(&pair).expect("ascii hex");
+            *byte = u8::from_str_radix(hex, 16).expect("invalid hex digit");
+        }
+        out
+    } else {
+        AccountId::from_str(s)
+            .expect("ProgramId must be 8 u32 limbs, a 64-char hex ImageID, or base58")
+            .into_value()
+    };
+    let mut pid: ProgramId = [0u32; 8];
+    for (limb, chunk) in pid.iter_mut().zip(bytes.chunks_exact(4)) {
+        *limb = u32::from_le_bytes(chunk.try_into().expect("4-byte chunk"));
+    }
+    pid
+}
+
+fn main() {
+    let args: Vec<String> = std::env::args().skip(1).collect();
+    let [ata_s, token_s, owner_s, def_s] = args.as_slice() else {
+        eprintln!("usage: ata_pdas <ata_pid> <token_pid> <owner> <definition>");
+        std::process::exit(1);
+    };
+    let ata = parse_pid(ata_s);
+    let token = parse_pid(token_s);
+    let owner = AccountId::from_str(owner_s).expect("owner must be base58");
+    let definition = AccountId::from_str(def_s).expect("definition must be base58");
+
+    let seed = compute_ata_seed(token, owner, definition);
+    println!("ata {}", get_associated_token_account_id(&ata, &seed));
+}