listProjections

listProjections — lists cash-flow projections owned by the caller, with optional filters.

Authentication: required

listProjections — lists cash-flow projections owned by the caller, with optional filters.

Used by budget and balance-forecast views to load all recurring expected
incomes/expenses. Filters are AND-combined: passing both isIncome and
category narrows to projections that match both.

Authentication: Required (Bearer token).

Parameters:
- isIncome (bool, optional): If set, filter to income (true) or expense (false) projections only.
- category (string, optional): If set, filter to projections with this transaction category.

Returns:
- projections ([]object): Projection records with fields:
  - id, userId, name, category, isIncome
  - startMonth, endMonth? (ISO 8601)
  - amount (number), repeatFrequency (MONTHLY/WEEKLY/YEARLY/NEVER/CUSTOM)
  - customRepeatFrequency? ({frequencyUnit, frequencyAmount})
  - overrides ([]object): Time-bound overrides.
  - createdAt, updatedAt (ISO 8601)

Errors:
- unauthenticated: missing or invalid Bearer token.
- internal: store failure.