fix(eas): build ios with xcode 26

Summary

App Store Connect rejected both iOS uploads built on sdk-53 (Xcode 16.4, iOS 18.5 SDK) with ITMS-90725: apps must be built with the iOS 26 SDK or later. latest (Xcode 27.1) failed for this SDK 53 project, so all five iOS profiles now pin macos-sequoia-15.6-xcode-26.0 (Xcode 26.0, Node 20.19.4).

Verification

• EAS build 0b582e0c from this branch (development profile, 0.0.9 build 3) FINISHED and was submitted to App Store Connect app 6826052581.

After merge

• eas.json is part of the fingerprint: runtimeVersion changes on both platforms. Rebuild staging iOS and Android before the next pnpm update:staging, or installed staging builds stop receiving OTA.
• SDK 53 on Xcode 26 is outside Expo's tested pairing; if iOS 26 UI looks off (liquid glass), set ios.infoPlist.UIDesignRequiresCompatibility: true. Long-term: move to SDK 54.

Review

Opus gate: PASS WITH SHOULD-FIX, 0 blocking (the two items above).

🤖 Generated with Claude Code