refactor(interface): rename to AggregatorV2V3Interface + add getRoundData

[hardyjosh]

The local oracle interface was named AggregatorV3Interface but its surface
is actually V2+V3: it includes the deprecated V2 latestAnswer() (needed for
Aave V3 and Compound V3 compatibility) and omitted V3's getRoundData(uint80).
Two integrator-facing footguns followed:

1. Anyone importing the canonical Chainlink AggregatorV3Interface and
   casting a PassthroughProtocolAdapter instance to it would compile against
   a five-method surface including getRoundData and runtime-revert when
   that selector was called.
2. The interface name suggested "V3" semantics while the contents matched
   Chainlink's own AggregatorV2V3Interface. New code reaching for the
   "real" V3 surface would silently lose latestAnswer without warning.

Renames the type to AggregatorV2V3Interface (matching Chainlink's own
hybrid type), moves the file to src/interface/IAggregatorV2V3.sol, and
adds full NatSpec including an explicit deprecation note on latestAnswer.
Adds the missing canonical getRoundData(uint80) method.

Implementations:

• BasePythOracleAdapter.getRoundData reverts with
  HistoricalRoundDataUnsupported(uint80). Pyth does not expose per-round
  history through this interface; callers needing point-in-time data should
  use Pyth's getPriceAtPublishTime or an indexer directly. The error
  selector is explicit so integrators can detect it on the wire.
• PassthroughProtocolAdapter.getRoundData forwards to the underlying
  oracle unchanged — a future Chainlink-backed oracle returns real
  historical data; a Pyth-backed oracle bubbles up the revert.

Tests:

• testPassthroughGetRoundData — happy path through Passthrough with a
  mocked underlying oracle returning real round data.
• testPassthroughGetRoundDataRevertSelectorPropagates — confirms the
  Pyth-backed revert selector + payload reach the integrator unchanged.
• testGetRoundDataAlwaysReverts — fuzzes the round ID into the
  BasePythOracleAdapter revert path.

Does not touch the in-adapter latestAnswer() consumption (Morpho still
calls latestAnswer without a staleness check — that's a separate Pass 5
finding tracked at MEDIUM and out of this PR's scope).

Found by /audit Pass 1 (Security), Pass 3 (Documentation), Pass 4 (Code
Quality), and Pass 5 (Correctness / Intent Verification) — A14p5-1
"Interface name asserts V3, contents are V2+V3 hybrid".

Co-Authored-By: Claude Opus 4.7 noreply@anthropic.com

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[hardyjosh]

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This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
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• refactor(interface): rename to AggregatorV2V3Interface + add getRoundData #222 : 2 dependent PRs (#223 , #224 ) 👈 (View in Graphite)
• chore: remove MultiPythOracleAdapter for Euler launch #238
• docs: README refresh + integrator notes for corporate-action auto-pause (RAI-325) #26 : 1 other dependent PR (#221 )
• feat(deploy): thread CorporateActionPauseConfig through unified deployers (RAI-322) #25
• test: auto-pause revert propagation through protocol adapters (RAI-321) #24
• feat(oracle): wire corporate-action auto-pause into BasePythOracleAdapter (RAI-320) #23
• feat(lib): LibCorporateActionsPause reader helper (RAI-319) #22
• docs(spec): corporate-action-aware auto-pause semantics (RAI-318) #21
• deps: migrate from git submodules to soldeer #237
• main

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