Typed Feature Flag Wrapper

Wrap our feature flag provider in a typed API. A flag name that does not exist should fail at compile time, and a missing provider should have a default. FLAGS Provider: [LAUNCHDARKLY | UNLEASH | POSTHOG | ENV | A SIMPLE MAP] Flags and defaults: [LIST NAME, TYPE, DEFAULT] Evaluation context: [USER ID, ORG ID, PLAN] Where they are read: [SERVER COMPONENTS | CLIENT | BOTH] DELIVER 1) A union of flag names and a typed getFlag(name) that returns the right type. No stringly mode in app code. 2) Defaults when the provider is down, and a log line when we serve the default. The default is the safe behavior (off for risky launches). 3) Server versus client: flags that change the HTML must be read on the server. Say how a client component gets the value without a flicker, or how it tolerates one. 4) Tests that flip a flag without a network call. 5) The cleanup rule: a flag older than the cleanup date in the definition fails a test or a lint. Show the definition field. Do not scatter provider SDK calls through components.