feat(ios): polish onboarding and native sign-in flow (#15217)

## Summary
- Reworks the iOS onboarding, native sign-in, and paywall flow so
first-install and cold-start entry stay native, adaptive, and aligned
with the current login/subscription gates.
- Removes onboarding swipe paging, refines onboarding/paywall layout
behavior, and keeps AI/paywall entry behavior consistent for logged-in
and subscribed users.
- Adds the new mobile all-docs empty states with localized copy and
dialog entry points, and closes the remaining review follow-ups by
removing the onboarding plan artifact and dropping the iOS AI
subscription bypass.

## Test plan
- Built the iOS app for simulator with `xcodebuild -workspace
App.xcworkspace -scheme App -configuration Debug -sdk iphonesimulator
-destination 'generic/platform=iOS Simulator' ARCHS=arm64
ONLY_ACTIVE_ARCH=YES CODE_SIGNING_ALLOWED=NO CODE_SIGNING_REQUIRED=NO
build` during the native onboarding/sign-in flow work.
- Let the repo pre-commit hooks run on the latest follow-up commit
(`prettier` + `eslint --fix`).
- Checked diagnostics for the edited TS/TSX files after the review
follow-up changes.
- Manually iterated on onboarding/native sign-in/paywall UI states in
simulator during implementation.

---------

Co-authored-by: DarkSky <darksky2048@gmail.com>

packages/frontend/apps/ios/App/Packages/AffinePaywall/Package.swift

@@ -16,14 +16,12 @@ let package = Package(
     ),
   ],
   dependencies: [
-    .package(path: "../AffineResources"),
     .package(url: "https://github.com/RevenueCat/purchases-ios-spm.git", from: "5.83.0"),
   ],
   targets: [
     .target(
       name: "AffinePaywall",
       dependencies: [
-        "AffineResources",
         .product(name: "RevenueCat", package: "purchases-ios-spm"),
       ]
     ),