r4bbit 7461c9552b feat(twap-oracle): implement CreateOraclePriceAccount instruction
Adds the CreateOraclePriceAccount instruction to the TWAP oracle program.
The instruction initialises a canonical OraclePriceAccount PDA for a given
price source and time window, seeding it with a non-zero initial price and
the current block timestamp so the account is immediately valid to consumers.

- PDA mirrors PriceObservations: derived from (oracle_program_id,
  price_source_id, window_duration) with a distinct seed constant, so each
  (source, window) pair maps to a distinct oracle price account that cannot
  collide with its corresponding observations account.

- source_id is not a parameter: it is always set to price_source.account_id.
  Accepting it as a free parameter would allow callers to register a price
  account that claims to represent a source it does not control. Deriving it
  from the authorized price source account closes that vector entirely.

- Authorization follows the same model as CreatePriceObservations:
  is_authorized = true on the price source proves the caller controls it; the
  PDA check ensures the supplied oracle price account address is the one
  derived from that specific source and window.

- The initial timestamp is read from the canonical 1-block LEZ clock
  (CLOCK_01_PROGRAM_ACCOUNT_ID), never from a caller-supplied value. The clock
  account_id is asserted, so a caller cannot substitute an account they
  control to forge the seeding timestamp.

- A zero price or zero timestamp is rejected at creation. Both are the
  "no valid price" sentinel consumers treat as unset, so an account must never
  be created in that state; the instruction asserts a non-zero initial_price
  and a non-zero clock timestamp.

- initial_price is a Q64.64 fixed-point value (real price = initial_price /
  2^64), matching the oracle price representation. The non-zero check rejects
  the sentinel but cannot validate scale — supplying a correctly-scaled value
  is the caller's responsibility.

Closes #129
2026-06-16 09:52:46 +02:00
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