refactor: unify PDA AccountId construction via AccountId::for_{public,private}_pda

Addresses the following review comment:

- "I think this should be a constructor `AccountId::for_private_pda`.
  Consider also removing the existing `impl From<(ProgramId, Seed)> for
  AccountId` for public pdas in favor of a `AccountId::for_public_pda`
  to have a unified way of constructing pdas"

I replaced `impl From<(&ProgramId, &PdaSeed)> for AccountId` with
`AccountId::for_public_pda(program_id: &ProgramId, seed: &PdaSeed) ->
Self` and replaced the free function `private_pda_account_id(...)`
with `AccountId::for_private_pda(program_id: &ProgramId, seed:
&PdaSeed, npk: &NullifierPublicKey) -> Self`. Both live in an inherent
`impl AccountId` block in nssa/core/src/program.rs next to the PDA
derivation logic. Migrated all call sites across nssa/core,
nssa/src/state.rs, nssa/src/validated_state_diff.rs,
program_methods/guest/src/bin/privacy_preserving_circuit.rs,
programs/amm/core, programs/associated_token_account/core, the example
tail-call binary, and the ATA tutorial doc. Test function names that
referenced the old free function were also renamed
(private_pda_account_id_* to for_private_pda_*).

programs/amm/core/src/lib.rs

@@ -135,10 +135,10 @@ pub fn compute_pool_pda(
     definition_token_a_id: AccountId,
     definition_token_b_id: AccountId,
 ) -> AccountId {
-    AccountId::from((
+    AccountId::for_public_pda(
         &amm_program_id,
         &compute_pool_pda_seed(definition_token_a_id, definition_token_b_id),
-    ))
+    )
 }
 
 #[must_use]
@@ -175,10 +175,10 @@ pub fn compute_vault_pda(
     pool_id: AccountId,
     definition_token_id: AccountId,
 ) -> AccountId {
-    AccountId::from((
+    AccountId::for_public_pda(
         &amm_program_id,
         &compute_vault_pda_seed(pool_id, definition_token_id),
-    ))
+    )
 }
 
 #[must_use]
@@ -199,7 +199,7 @@ pub fn compute_vault_pda_seed(pool_id: AccountId, definition_token_id: AccountId
 
 #[must_use]
 pub fn compute_liquidity_token_pda(amm_program_id: ProgramId, pool_id: AccountId) -> AccountId {
-    AccountId::from((&amm_program_id, &compute_liquidity_token_pda_seed(pool_id)))
+    AccountId::for_public_pda(&amm_program_id, &compute_liquidity_token_pda_seed(pool_id))
 }
 
 #[must_use]

programs/associated_token_account/core/src/lib.rs

@@ -61,7 +61,7 @@ pub fn compute_ata_seed(owner_id: AccountId, definition_id: AccountId) -> PdaSee
 }
 
 pub fn get_associated_token_account_id(ata_program_id: &ProgramId, seed: &PdaSeed) -> AccountId {
-    AccountId::from((ata_program_id, seed))
+    AccountId::for_public_pda(ata_program_id, seed)
 }
 
 /// Verify the ATA's address matches `(ata_program_id, owner, definition)` and return