[Roxas2712]

An API-3 mod that selects an opponent by battlerId == 3 currently receives a detached battler record on Gen2Recomped. Gen1Recomp supplies a numeric selector (or nil for the native default). Align the GBA API-3 hook input, including the actual single/double controllers.

The public hook now receives (battle, battlerId). Zero-argument next preserves the current request; omitted/nil selectors ask for the native default; explicit selectors cross back to the actual native actor. Nested and reentrant hooks preserve each request's selector, and native errors clean up the scope without retrying AI. API-1/2 native and API-2 unified retain their existing actor argument and identity contracts.

Also retain execution ownership when a hook queries the other flank's native AI: the caller executes the delegated choice and spends its own selected PP slot. Querying the other flank does not spend that flank's PP.

Stacked on #190. Review feature commit 206052fb relative to that prerequisite (11 files).

Validation:

• 438/438 focused argument checks for FireRed/Emerald: real public SDK, nil/explicit selectors, position-based choices, forwarding, nested hooks, reentry, foreign native queries and actual PP consumption.
• Actual native single/double turn queues, mixed native/public hooks, API-1/2 legacy identity and native-error cleanup are executed.
• All existing 1,252/1,252 move-result checks remain green.
• Pinned unchanged read-only Gen1 reference 535a5ec088c1ae1bf4d91dd3e35a56f64cf46d91: 12 isolated worker runs / 162 paired observations pass, combining the existing API-2/API-3 move-result contract with API-3 argument cases.
• Full local quick run: 78/88 engine suites versus 77/87 on clean Normalize public GBA enemy move choices and native PP ownership #190. The exact Counter of all 27 inherited FAIL lines across ten suites matches; no new failures. SDK 3/3 and B30 pass.
• actionlint and git diff --check pass.

Scope: API-3 GBA input selectors and execution ownership. Native output record fields, public item/switch/watch actions, explicit move-target conversion, damage amounts and RNG traces remain separate contracts. Gen1 is used as a read-only reference; no Gen1 patch or publication is required. Hosted CI is reported separately from local validation.

Combined-fork validation: integrated into Roxas2712:codex/portability-testing, production runtime 6bb17f0. All 209/209 engine suites, 3/3 SDK suites and B30 pass. The same 12-worker / 162-observation pinned comparison passes on this runtime; public priority integration remains 32/32. Integration preserves native GBA turn-word preparation, both enemy selections before turn reset, held-item ID translation and identity-roll restore behavior.

Hosted CI: all three workflows report action_required pending maintainer approval. The dedicated contract workflow has zero executed jobs. These are separate from local acceptance.