feat(amm): create TWAP price observations on behalf of the pool

Add a `CreatePriceObservations` instruction that registers a TWAP
price-observations account for a pool over a time window, via a chained
call to the configured TWAP oracle program. The pool acts as the price
source: the AMM authorizes it with its pool PDA seed so the oracle ties
the feed to that pool.

The feed's initial tick is read from the pool's authoritative
`CurrentTickAccount` (validated against its pool-derived PDA) rather than
being supplied by the caller, so the feed cannot be seeded at a forged
price — mirroring what `RecordTick` does. The clock is verified to be the
canonical 1-block LEZ clock, and creation is rejected if the observations
account already exists.

To support the chained call, `AmmConfig` and the `Initialize` instruction
are extended with a `twap_oracle_program_id` that the instruction reads.

programs/amm/src/initialize.rs

@@ -7,10 +7,11 @@ use nssa_core::{
 /// Initializes the AMM Program by creating its singleton configuration account.
 ///
 /// The config account is a PDA derived from the constant `"CONFIG"` seed
-/// (`compute_config_pda(amm_program_id)`) and stores `token_program_id` (the Token Program the
-/// AMM issues every chained call to) and `authority` (the admin allowed to change configuration
-/// later via `update_config`). Its existence is the Program's "initialized" flag: the
-/// chained-call instructions read the Token Program ID from it and reject calls until it exists.
+/// (`compute_config_pda(amm_program_id)`) and stores the program IDs the AMM issues chained calls
+/// to — `token_program_id` (the Token Program) and `twap_oracle_program_id` (the TWAP oracle) —
+/// plus `authority` (the admin allowed to change configuration later via `update_config`). Its
+/// existence is the Program's "initialized" flag: the chained-call instructions read these
+/// program IDs from it and reject calls until it exists.
 ///
 /// # Panics
 /// Panics if:
@@ -19,6 +20,7 @@ use nssa_core::{
 pub fn initialize(
     config: AccountWithMetadata,
     token_program_id: ProgramId,
+    twap_oracle_program_id: ProgramId,
     authority: AccountId,
     amm_program_id: ProgramId,
 ) -> Vec<AccountPostState> {
@@ -36,6 +38,7 @@ pub fn initialize(
     let mut config_post = config.account.clone();
     config_post.data = Data::from(&AmmConfig {
         token_program_id,
+        twap_oracle_program_id,
         authority,
     });
 
@@ -54,6 +57,7 @@ mod tests {
 
     const AMM_PROGRAM_ID: ProgramId = [42; 8];
     const TOKEN_PROGRAM_ID: ProgramId = [15; 8];
+    const TWAP_ORACLE_PROGRAM_ID: ProgramId = [77; 8];
 
     fn authority() -> AccountId {
         AccountId::new([9; 32])
@@ -72,6 +76,7 @@ mod tests {
         let post_states = initialize(
             config_uninit(),
             TOKEN_PROGRAM_ID,
+            TWAP_ORACLE_PROGRAM_ID,
             authority(),
             AMM_PROGRAM_ID,
         );
@@ -83,16 +88,18 @@ mod tests {
     }
 
     #[test]
-    fn stores_token_program_id_and_authority() {
+    fn stores_program_ids_and_authority() {
         let post_states = initialize(
             config_uninit(),
             TOKEN_PROGRAM_ID,
+            TWAP_ORACLE_PROGRAM_ID,
             authority(),
             AMM_PROGRAM_ID,
         );
         let config = AmmConfig::try_from(&post_states[0].account().data)
             .expect("post state must contain a valid AmmConfig");
         assert_eq!(config.token_program_id, TOKEN_PROGRAM_ID);
+        assert_eq!(config.twap_oracle_program_id, TWAP_ORACLE_PROGRAM_ID);
         assert_eq!(config.authority, authority());
     }
 
@@ -101,7 +108,13 @@ mod tests {
     fn wrong_config_account_id_panics() {
         let mut wrong = config_uninit();
         wrong.account_id = AccountId::new([0; 32]);
-        initialize(wrong, TOKEN_PROGRAM_ID, authority(), AMM_PROGRAM_ID);
+        initialize(
+            wrong,
+            TOKEN_PROGRAM_ID,
+            TWAP_ORACLE_PROGRAM_ID,
+            authority(),
+            AMM_PROGRAM_ID,
+        );
     }
 
     #[test]
@@ -110,9 +123,16 @@ mod tests {
         let mut initialized = config_uninit();
         initialized.account.data = Data::from(&AmmConfig {
             token_program_id: TOKEN_PROGRAM_ID,
+            twap_oracle_program_id: TWAP_ORACLE_PROGRAM_ID,
             authority: authority(),
         });
         initialized.account.nonce = Nonce(0);
-        initialize(initialized, TOKEN_PROGRAM_ID, authority(), AMM_PROGRAM_ID);
+        initialize(
+            initialized,
+            TOKEN_PROGRAM_ID,
+            TWAP_ORACLE_PROGRAM_ID,
+            authority(),
+            AMM_PROGRAM_ID,
+        );
     }
 }