fw-05 step 02 — Join reactivity to rendering

Goal

The join that changes the cost curve: wrap each component's render in a fw-03 effect.

Tasks

1. Components with lifecycle.
2. Wrap each component's render in an effect, so reactive reads subscribe that component's render.
3. Demonstrate: change a value read by a deep child; confirm the parent does not re-render. Compare with fw-02, where a state change re-renders the subtree.
4. Scheduler: deduplicate and flush component updates on a microtask. Reproduce the un-scheduled case where one component renders three times in a tick.
5. Event handler identity: measure naive remove-and-re-add versus a stable indirection.
6. Handle a component whose dependencies change between renders (a conditional read) — confirm fw-03's cleanup handles it.

Done when

• Parent-does-not-re-render demonstrated and measured against fw-02
• Scheduler dedupes; the un-scheduled case reproduced first
• You can state where React's and Vue's defaults each place the burden