Get Feature Flags

Resolved boolean feature flags for the requesting user.

Field naming follows the canonical agent names in the product:

• finetune_agent_enabled: Claude-powered Fine-tune chat agent. Renamed from mle_agent_enabled by ENG-6245; ENG-6613 retired the deprecated twin, so this is the only agent field published.
• user_data_export_enabled: Self-serve GDPR SAR export (ENG-2128). Off by default and gating both the settings panel and the route, so the UI cannot offer an archive the backend refuses to build.
• cancellation_immediate_refund_option_enabled: Whether the "cancel immediately + pro-rated refund" button is shown alongside the primary "cancel — keep access until period end" button. Also enforced server-side on the cancellation endpoints, so disabling it actually blocks the refund path, not just the button.
• prepaid_billing_enabled: Prepaid-credit onboarding — a new team starts at a zero balance and is sent straight to Stripe Checkout to top up (ENG-5956 cutoff). Defaults on; a Datadog Disabled env uses this code default. Explicit Datadog false remains the incident kill switch. Purchase-credits no longer refuses free-plan teams.

ENG-5651 withdrew research_agent_enabled (Deep Research, formerly auto_agent_enabled) and continuous_adaptation_agent_enabled (the autonomous fine-tuning loop, formerly data_engine_agent_enabled). Both gated surfaces that no longer exist, so the fields are gone from the contract rather than pinned to False. The removal is temporary: the Datadog keys are deliberately left in place, so restoring either feature means re-adding its field and helper — not recreating the flag.