refactor: migrate to Annotated type aliases for FastAPI dependencies

[emiliano-gandini-outeda]

Replace all inline Depends(...) calls and raw Annotated[..., Depends(...)] annotations with centralized type aliases. Route signatures are cleaner and new modules can reuse the same aliases without repeating import boilerplate.

Changes

Infrastructure

• infrastructure/dependencies.py: 9 shared aliases: AsyncSessionDep, CurrentUserDep, CurrentSuperUserDep, OptionalUserDep, SessionManagerDep, CurrentSessionDataDep, OAuth2FormDep, GoogleOAuthProviderDep, OAuthStateStorageDep

Per-module service aliases

• modules/{user,tier,rate_limit,api_keys}/dependencies.py: service aliases per feature, factory functions moved out of route files

Route files migrated

Module	Endpoints	Notes
user/routes.py	11	Switch to aliases, param reordering
tier/routes.py	2	Switch to TierServiceDep
rate_limit/routes.py	4	Switch to RateLimitServiceDep
api_keys/routes.py	8	Switch to aliases, reorder key_id: Path
auth/routes.py	6	Switch to aliases, reorder Query params

Docs

• endpoints.md: DI intro section with alias reference tables
• development.md: custom dependency walkthrough with alias registration example
• README.md: feature bullet for Annotated type aliases

Migration pattern

# Before
async def get_item(
    db: AsyncSession = Depends(async_session),
    service: ItemService = Depends(get_item_service),
) -> dict[str, Any]:
    ...
# After
async def get_item(
    db: AsyncSessionDep,
    service: ItemServiceDep,
) -> dict[str, Any]:
    ...