fix(ios): publish final IME state before legacy text

[bytemain]

Summary

• publish the complete iOS text input state before the legacy text callback for both marked and committed text
• route both callbacks through one production KRTextInputEventSequencer and one frozen native snapshot
• bind large marked-to-committed diagnostics to one uninterrupted edit session; blur and every programmatic text-state mutation invalidate pending attribution
• add a native executable fixture for callback order/snapshot identity and same-session vs blur/controlled-sync attribution
• cover the observed 31-character marked text to 3-character commit in Compose, verifying the legacy echo is consumed with no controlled native writeback

Validation

• tools/ios-renderer-tests/run-text-input-event-sequencer-test.sh
• ./gradlew :compose:testDebugUnitTest
• ./gradlew :core:compileKotlinIosSimulatorArm64 :compose:compileKotlinIosSimulatorArm64 :compose:compileTestKotlinIosSimulatorArm64
• xcodebuild -workspace iosApp/iosApp.xcworkspace -scheme OpenKuiklyIOSRender -configuration Debug -sdk iphonesimulator -destination 'generic/platform=iOS Simulator' CODE_SIGNING_ALLOWED=NO GCC_TREAT_WARNINGS_AS_ERRORS=YES SWIFT_TREAT_WARNINGS_AS_ERRORS=YES build
• actionlint -ignore SC1083 .github/workflows/compose-pr.yml
• shellcheck tools/ios-renderer-tests/run-text-input-event-sequencer-test.sh

Scope / caveat

This closes the deterministic callback-order defect observed at the candidate-commit boundary. The original one-off crash stack is entirely inside UIKit/TextKit on iOS 27, so source/unit/build validation must not be represented as physical-device crash closure until that OS/device path is reproduced.