[Chore] Add KNOWN_POOLS early-exit guard in api/v1/vaults/[vaultId].ts #279

Problem

api/v1/vaults/[vaultId].ts calls fetchAllVaults() before checking whether the requested vaultId is known. On a cache miss, this triggers a full DeFiLlama round-trip only to return a 404. An unknown vault ID should be rejected immediately with no I/O.

Fix

Check KNOWN_POOLS (an O(1) map lookup by vault ID) before calling fetchAllVaults() and return 404 immediately for unrecognised IDs:

if (!KNOWN_POOLS[vaultId]) {
  return res.status(404).json({ error: "Vault not found" });
}
const vaults = await fetchAllVaults();

Acceptance Criteria

• pnpm lint && pnpm typecheck && pnpm test pass with no errors
• A request for an unknown vault ID returns 404 without making any network call