navigation-flow

# Maintain UIKitUltra Navigation Flow Use this LOCAL contributor skill for built-in UIKitUltra navigation source work. ## Load the smallest decision-complete context 1. Assume root/architecture/skill routing already selected this skill and `NAVIGATION_SYSTEM.md`; do not re-read `AGENTS.md`/`SKILL_INDEX.md` unless that context is genuinely missing or stale. 2. Use [`NAVIGATION_SYSTEM.md`](../../architecture/NAVIGATION_SYSTEM.md) as the primary owner. 3. Add only what the change needs: - [`RUNTIME_MODEL.md`](../../architecture/RUNTIME_MODEL.md) for lifecycle/deferred transitions; - [`PLATFORM_ABSTRACTION.md`](../../architecture/PLATFORM_ABSTRACTION.md) for iOS/tvOS/macOS separation; - [`FLUENT_CHAIN_CONTRACT.md`](../../architecture/FLUENT_CHAIN_CONTRACT.md) for changed public configuration APIs. 4. Use [`SOURCE_MAP.md`](../../SOURCE_MAP.md) only if the affected source location/ownership is not already known. ## Plan checklist - Identify exact platform scope and current native navigation substrate. - Identify push/pop or transition lifecycle behavior affected. - Check fluent API compatibility for configuration changes. - Check recognizer/delegate interactions when swipe-back behavior is involved. - Distinguish local convenience behavior from a new global navigation policy. ## Implementation rules - Preserve platform-specific navigation separation. - Keep transitions and navigation effects explicit; do not introduce hidden global behavior. - Preserve fluent `Self` return semantics for public configuration methods. - Keep lifecycle assumptions aligned with the current runtime owner. - Preserve native navigation/delegate ownership unless architecture is explicitly re-opened. ## Audit Verify: - intentional platform divergence remains correct; - swipe-back gating/delegate behavior is preserved when in scope; - transition helpers remain explicit opt-in APIs; - no platform leakage appears in shared contracts; - fluent/reference semantics remain intact; - unrelated source/governance remains untouched. Stop and re-plan if the work requires a new navigation lifecycle/coordination model rather than an implementation inside the existing architecture.