fix(manager): RedisStorage expects a client instance, not a URL string

[PenguinzTech]

Summary

Verifying manager's Dockerfile end-to-end now that penguin-limiter is published on PyPI (was previously missing entirely, blocking any build). The image now builds cleanly, but create_app() crashed at boot:

TypeError: RedisStorage.__init__() got an unexpected keyword argument 'url'

penguin_limiter.storage.redis_store.RedisStorage.__init__(self, client, key_prefix=...) takes an already-constructed redis-py client (it calls client.register_script(...) internally) — not a connection URL string. Manager called RedisStorage(url=_storage_url). This is the first time this code path has ever actually run, since the package didn't exist until this week.

Fix

Construct the redis-py client first, pass that:

_storage = RedisStorage(client=redis.Redis.from_url(_storage_url))

Verification

• Built the real manager/backend/Dockerfile end-to-end (no stripped dependencies)
• Confirmed penguin-limiter resolves and installs from PyPI
• Ran the container via its actual entrypoint (gunicorn, not just an import check) against a live Valkey instance
• All 4 gunicorn workers boot; curl /health returns {"status":"healthy"} with HTTP 200; container stays up

Test plan

• docker build succeeds
• Container runs via real entrypoint against live Valkey
• /health returns 200
• Pre-commit hooks (gitleaks, flake8, Dockerfile lint) pass