WIP: checkpoint Wii native IMU and upstream IR bridge

Pause Wii pointing work with firmware 0.33-wii-trace installed. Preserve the pinned libogc IR pipeline, calibrated native IMU, software BOOTSEL, and standard camera sensitivity trial.

Tracking instability, tracking loss, and ineffective vertical movement remain unresolved. Level-2 camera filtering is not hardware-qualified. Nine targeted regression tests pass; firmware and persistent storage were verified after flashing.

tests/test_wii_ir_pointer_native.py

@@ -0,0 +1,75 @@
+from __future__ import annotations
+
+import shutil
+import subprocess
+import sys
+from pathlib import Path
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[1] / "tools"))
+
+from prepare_libogc_ir import prepare
+
+
+@pytest.mark.parametrize(
+    "native_bridge", [False, True], ids=["legacy-mouse", "native-wii"]
+)
+def test_wii_ir_pointer_output_contract(tmp_path: Path, native_bridge: bool) -> None:
+    root = Path(__file__).resolve().parents[1]
+    compiler = shutil.which("c++") or shutil.which("g++")
+    assert compiler is not None, "a host C++ compiler is required"
+    executable = tmp_path / "wii_ir_pointer_test"
+    defines = ["-DSWITCH_PICO_WII_IR=1"]
+    defines.append(
+        "-DSWITCH2_BRIDGE_WII_INPUT=1"
+        if native_bridge
+        else "-DSWITCH_PICO_WII_IR_MOUSE=1"
+    )
+    if native_bridge:
+        c_compiler = shutil.which("cc")
+        assert c_compiler is not None, "a host C compiler is required"
+        generated = prepare(tmp_path / "libogc_ir.c")
+        ir_object = tmp_path / "libogc_ir.o"
+        subprocess.run(
+            [
+                c_compiler,
+                "-std=c11",
+                "-Wall",
+                "-Wextra",
+                "-Werror",
+                "-pedantic",
+                f"-I{root / 'external'}",
+                "-c",
+                str(generated),
+                "-o",
+                str(ir_object),
+            ],
+            check=True,
+            cwd=root,
+        )
+        ir_sources = [str(ir_object)]
+    else:
+        ir_sources = [str(root / "src" / "firmware" / "input" / "wii_ir_tracker.cpp")]
+    subprocess.run(
+        [
+            compiler,
+            "-std=c++17",
+            "-Wall",
+            "-Wextra",
+            "-Werror",
+            "-pedantic",
+            *defines,
+            f"-I{root / 'tests' / 'wii_ir_aiming_native_stubs'}",
+            f"-I{root / 'src' / 'firmware'}",
+            f"-I{root / 'external'}",
+            str(root / "tests" / "wii_ir_pointer_test.cpp"),
+            str(root / "src" / "firmware" / "input" / "wii_ir_pointer.cpp"),
+            *ir_sources,
+            "-o",
+            str(executable),
+        ],
+        check=True,
+        cwd=root,
+    )
+    subprocess.run([str(executable)], check=True, cwd=root)