fix(ios): support Xcode 16+ team detection and fix ntohl build error

Xcode 16+/26 no longer writes IDEProvisioningTeams to the preferences
plist, breaking ios-team-id.sh for newly signed-in accounts. Add
provisioning profile fallback and actionable error when an account
exists but no team ID can be resolved. Also replace ntohl() with
UInt32(bigEndian:) for Swift 6 compatibility and gitignore Xcode
build output directories.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.gitignore

@@ -102,6 +102,12 @@ skills-lock.json
 
 # Local iOS signing overrides
 apps/ios/LocalSigning.xcconfig
+
+# Xcode build directories (xcodebuild output)
+apps/ios/build/
+apps/shared/OpenClawKit/build/
+Swabble/build/
+
 # Generated protocol schema (produced via pnpm protocol:gen)
 dist/protocol.schema.json
 .ant-colony/