Connect PostHog to tasu

Instrument my mobile app with PostHog so every part of tasu works: the conversion funnel, screen-by-screen onboarding drop-off, main-app usage and retention. tasu reads these EXACT event names. Do not track prices, amounts or revenue — revenue comes from RevenueCat/Superwall, not analytics.

1. SDK. If PostHog isn't installed yet, add the official SDK for this project's platform (posthog-ios, posthog-android, posthog-react-native, or posthog-flutter) and initialize it once at app launch. Leave a clearly marked placeholder where I'll paste my PostHog project API key and host (US or EU).

2. Identity — this is what lets tasu join behavior to revenue. Call PostHog's identify with our internal user id as soon as it exists (after signup/login). If RevenueCat is in this codebase, use the SAME id you pass to RevenueCat as the app user ID, so the two datasets describe the same person.

3. Map the ENTIRE onboarding flow. Search the codebase and list, in order, every screen a brand-new user can see between first app open and reaching the main app. Do not skip any — include: splash/welcome, value or intro slides, every question/quiz/personalization step, name or goal inputs, notification permission, app-tracking-transparency permission, account creation or sign-in, loading/"building your plan" screens, the paywall, and any post-paywall screens (discount offer, rating request, tutorial). Give each screen a short, stable snake_case id, e.g. "welcome", "goal_question", "notifications_permission", "plan_loading", "paywall", "discount_offer".

4. Instrument EVERY screen from that list. The moment each screen becomes visible, capture:
   - Event name: "onboarding_screen_viewed" (exactly this, the same name on every screen)
   - Properties:
     - "screen_name" = the screen's stable id
     - "step" = its 1-based position actually shown in that session
     - "screen_type" = exactly one of: "value" | "question" | "input" | "permission" | "signup" | "loading" | "paywall" | "offer" | "other"
   Every screen fires it, no exceptions — this powers tasu's by-step AND by-type drop-off views.

5. Track these five funnel events with EXACTLY these names:
   - "app_opened" — every app launch and every return to the foreground.
   - "onboarding_completed" — the moment the user finishes the last onboarding screen and enters the main app.
   - "paywall_viewed" — every time a paywall becomes visible, with property "placement" = "onboarding" or "in_app". Fire it in addition to that screen's "onboarding_screen_viewed".
   - "trial_started" — when a free trial actually starts; hook the purchase success / RevenueCat customer-info callback, not the button tap.
   - "subscription_started" — when a paid subscription activates or a trial converts to paid (RevenueCat callback level if available). No price or amount properties needed.

6. Main-app usage — powers tasu's retention and habit views:
   - "screen_viewed" with property "screen_name" (stable snake_case id) every time a main-app screen or tab becomes visible AFTER onboarding. Cover every screen a user can reach.
   - The core repeat actions of this app — the 3 to 10 things users do again and again that make this app what it is (examples from other apps: "workout_logged", "entry_created", "lesson_completed") — each as its OWN event, snake_case, past tense. These are what tasu correlates with paying vs churned users to find the activation metric.

7. Attribution (unlocks tasu's Revenue-by-channel view): add one onboarding screen that asks new users how they found you (App Store, TikTok, Instagram, friend, etc.), and fire "attribution_selected" with property "channel" = their choice. Keep it a single tap.

8. Do not rename, remove, or duplicate existing analytics events — only add what's missing. If an equivalent event already exists under a different name, keep it AND add the tasu name alongside.

When you're done, output: (a) the ordered onboarding screen list with each screen's id, screen_type and file path, (b) the main-app screens and core action events you added, (c) every file you changed, and (d) exactly where I paste the PostHog API key.