Scene.set() JS lifecycle, UI sprite caching, emulator test scripts

- Add Scene.set(module) so JerryScript can switch scenes via
  require()'d {init, update, dispose} modules; wire it into
  engineUpdate() and rework overworldscene.js/init.js to the new shape.
- Fix scriptManagerExecFile() never pushing its own file's directory
  onto the require() dir stack, breaking relative require() calls from
  a top-level entry script (e.g. init.js -> ./overworldscene.js).
- Cache sprite geometry across frames for uislider/uitab/uiframe
  (dialogs/textbox/settings) and give uitextbox a per-page glyph cache
  instead of one spriteBatchBuffer call per visible character. uiconsole
  drops its alloc/free vertex buffer for a fixed-size one. uifps skips
  rebuilding its label when the text hasn't changed.
- Add PSP_OPTIMIZATION_PLAN.md and a handful of UI/spritebatch unit
  tests covering the new caching logic.
- Add Dolphin/PPSSPP emulator smoke-test scripts (+ Docker variants and
  CI jobs) for GameCube/Wii/PSP.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docker/dolphin-test/Dockerfile

@@ -0,0 +1,7 @@
+FROM ghcr.io/extremscorner/libogc2
+WORKDIR /workdir
+RUN apt update && \
+    dkp-pacman -Syu --noconfirm && \
+    apt install -y python3 python3-pip python3-polib python3-pil python3-dotenv python3-pyqt5 python3-opengl xorriso dolphin-emu xvfb && \
+    dkp-pacman -S --needed --noconfirm gamecube-sdl2 ppc-liblzma ppc-libzip libogc2 gamecube-tools ppc-libmad ppc-zlib-ng ppc-liblzma ppc-bzip2 ppc-zstd
+VOLUME ["/workdir"]

docker/psp-test/Dockerfile

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+FROM pspdev/pspdev:latest
+WORKDIR /workdir
+RUN apk add --no-cache \
+  python3 \
+  py3-pip \
+  py3-dotenv \
+  git \
+  cmake \
+  make \
+  g++ \
+  sdl2-dev \
+  zlib-dev \
+  linux-headers
+
+# PPSSPP has no Alpine/Linux distro package -- build the "PPSSPPHeadless"
+# target (the CLI/no-window build PPSSPP's own CI uses for automated runs)
+# from source instead. The target name and exact CMake options have moved
+# around across PPSSPP versions -- if this breaks, check
+# https://github.com/hrydgard/ppsspp's CMakeLists.txt for the current name.
+RUN git clone --recursive --depth 1 \
+    https://github.com/hrydgard/ppsspp.git /opt/ppsspp && \
+  cd /opt/ppsspp && \
+  cmake -B build -DCMAKE_BUILD_TYPE=Release && \
+  cmake --build build --target PPSSPPHeadless -- -j$(nproc) && \
+  cp build/PPSSPPHeadless /usr/local/bin/PPSSPPHeadless && \
+  rm -rf /opt/ppsspp
+
+VOLUME ["/workdir"]