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/tests.rs

@@ -30,6 +30,7 @@ use crate::{
 
 const TOKEN_PROGRAM_ID: ProgramId = [15; 8];
 const AMM_PROGRAM_ID: ProgramId = [42; 8];
+const TWAP_ORACLE_PROGRAM_ID: ProgramId = [77; 8];
 const MALICIOUS_TOKEN_PROGRAM_ID: ProgramId = [99; 8];
 
 struct BalanceForTests;
@@ -628,6 +629,7 @@ impl AccountWithMetadataForTests {
                 balance: 0u128,
                 data: Data::from(&AmmConfig {
                     token_program_id: TOKEN_PROGRAM_ID,
+                    twap_oracle_program_id: TWAP_ORACLE_PROGRAM_ID,
                     authority: AccountId::new([9; 32]),
                 }),
                 nonce: Nonce(0),