[Roxas2712]

Run native GSC Protect/Endure on the existing battler, RNG and actual action entry: source-model nonzero-byte odds, opponent-first and Substitute failures, and first-side identity through switches. A self-protection effect now reaches its own failed-use command even when the opposing battler protects. The separate GSC command revision and handshake/fingerprint domain prevent old rules entering changed lockstep; other editions retain this older host's existing wire behavior.

Depends on #392 (volatile), #390 (priority), #351 (native model) and #124 (native mod host). This is independently adapted and tested on the older offered host, not a copy of fork-only checkpoint/GBA protocol backends. The full comparison against upstream main also includes those unmerged prerequisites.

Independent focused checks: native protection 3796/3796, actual link roles 66/66, protocol 37/37, priority 83/83, volatile state 423/423; frozen Gen1 comparison 30,624 effect cases / 165,336 comparisons. The exact official whole-host command also ran against both its priority base and this offered source: 65/76 versus 69/80 engine suites, the same eleven pre-existing failing suites in both, SDK 3/3 in both. Thus this older prerequisite stack is not globally green; the four added suites pass without adding a whole-host failure. Details and reference scope are in docs/native-gen2-protection.md. No unchanged-mod/GPU, complete turn/model or release acceptance is claimed. The fork's semantic-checkpoint results are not claimed for this host.

Contributions by Roxas2712 — https://github.com/Roxas2712. Offered to Cedric / UNDERdecoded under https://github.com/Roxas2712/Gen2Recomped/blob/main/LICENSE-ROXAS2712.md, including visible credit and preservation of prior/third-party permissions.