Port Reflect and Light Screen

BattleCommand_Screen and HandleScreens run natively. Each side owns
independent five-turn counters that include the setup turn, do not
refresh on repeated use and survive enemy send-outs. Screens expire in
the original non-Link order with ROM messages; the existing damage path
already doubles the right defense and keeps the critical/stage rule.
This closes the only refusal found by the Route 30 stress run
(Chikorita's Reflect).

The NPC movement test now reads the ROM in beforeAll, so it skips
cleanly without one.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

docs/PLAN.md

@@ -75,7 +75,13 @@ The emulator-backed prototype is now at `/reference.html`. The default applicati
 - Hidden items (`BGEVENT_ITEM`) run `HiddenItemScript`.
 - Route 30 and its Berry house are enabled. Mr. Pokémon's house and Route 31 stay closed; Youngster Joey (after the Egg) needs phone registration and stays hidden until then, as in the original.
 - A refused trainer script does not restart until the player moves, so a rollback cannot trap the player in a trainer's sight.
-- A local stress run of 1,080 Route 30 battles (three starters, four levels, three times of day, both trainers and wild encounters) found one refusal: Chikorita's Reflect at level 12 (`screen`, not yet ported).
+- A local stress run of 1,080 Route 30 battles (three starters, four levels, three times of day, both trainers and wild encounters) found one refusal: Chikorita's Reflect at level 12 (`screen`), now addressed by the screen increment below.
+
+## Implemented: Reflect and Light Screen
+
+- Both moves execute their ROM effect scripts, set independent five-turn counters and fail without refreshing an active screen. The setup turn counts toward expiration.
+- Screens persist across enemy send-outs and expire in the original non-Link order, with ROM messages. Physical/special defenses and critical-hit stage rules use the existing damage path.
+- Local-ROM regressions cover both sides, repeated use and PP, concurrent durations, send-out persistence, expiration order and damage stats. These checks are not an emulator comparison of the screen routines.
 
 ## In progress: native battles