iOS build fixes/prep for TestFlight

mobile/docs/iOS_TESTFLIGHT.md

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+# iOS TestFlight GitHub Action
+
+This repository now includes `.github/workflows/ios-testflight.yml`, which builds a **signed** iOS IPA and uploads it to TestFlight.
+
+## What must be in the repo
+
+- The workflow file itself: `.github/workflows/ios-testflight.yml`
+- Existing app signing identifiers in Xcode:
+  - Bundle ID `am.sure.mobile` (or your custom value in the workflow)
+- Flutter assets and source already in `mobile/`
+
+## Required GitHub Secrets
+
+Set these in **Settings → Secrets and variables → Actions**:
+
+- `APP_STORE_CONNECT_API_KEY_ID`
+- `APP_STORE_CONNECT_API_ISSUER_ID`
+- `APP_STORE_CONNECT_API_KEY_BASE64`
+  - Base64 version of the `.p8` private key content
+- `IOS_TEAM_ID`
+- `IOS_KEYCHAIN_PASSWORD`
+- `IOS_DISTRIBUTION_P12_BASE64`
+- `IOS_DISTRIBUTION_P12_PASSWORD`
+- `IOS_DISTRIBUTION_CERT_NAME`
+  - Usually `iPhone Distribution`
+- `IOS_PROVISIONING_PROFILE_NAME`
+- `IOS_PROVISIONING_PROFILE_BASE64`
+
+> Do **not** commit private keys, `.p12` files, or `.p8` files to the repository.
+
+## Triggering
+
+- Run manually: **Actions → iOS TestFlight → Run workflow**
+- Push a tag that matches `ios-v*` (for example `ios-v1.2.3`)
+
+## Recommended App Store Connect setup
+
+- Use an API Key with App Manager or Developer role
+- Create/download an iOS Distribution certificate (`.p12`), convert to base64 for `IOS_DISTRIBUTION_P12_BASE64`
+- Create and distribute an **App Store** provisioning profile for `am.sure.mobile`
+- Base64-encode the `.mobileprovision` file for `IOS_PROVISIONING_PROFILE_BASE64`
+
+## Output
+
+- IPA artifact: `ios-ipa-testflight`
+- Uploaded IPA to TestFlight on successful upload step
+