Wire up Linux and Windows exports

export_presets.cfg is hand-written (no editor GUI available here): a
minimal preset per platform (name, platform, path, x86_64
architecture) is enough, since Godot fills every other option from
its platform defaults. tools/setup.sh now also fetches the matching
export templates (~1.2GB, cached outside the repo like the Godot
binary itself) -- note the directory it unpacks into uses a dot
before "stable" while .godot-version and the download URLs use a
hyphen, two different spellings of the same version that are easy to
conflate.

Both make export-linux and make export-windows now actually run and
produce a working package; tests/ and addons/gut/ are excluded from
the exported .pck (124KB vs 1.5MB before -- a dev-only dependency has
no business shipping to a child's machine). The Linux binary was
smoke-tested headless and boots cleanly; the Windows .exe could only
be confirmed as a valid PE32+ binary, since no Windows machine or
Wine is available in this environment -- flagged in
docs/testing/manual-checklist.md rather than claimed as verified.

This closes out every step in the launch prompt's "Ordre de
construction." README status lines updated to reflect the first
playable prototype rather than a bare skeleton.

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

tools/setup.sh

@@ -28,6 +28,25 @@ else
     echo "Godot deja present dans ${GODOT_BIN}."
 fi
 
+# Godot nomme ce dossier avec un point avant "stable" (ex. "4.6.3.stable"),
+# alors que .godot-version et les URLs de telechargement utilisent un tiret
+# (ex. "4.6.3-stable") : les deux formats sont distincts, pas de typo ici.
+GODOT_TEMPLATE_VERSION="${GODOT_VERSION/-/.}"
+EXPORT_TEMPLATES_DIR="${HOME}/.local/share/godot/export_templates/${GODOT_TEMPLATE_VERSION}"
+if [ ! -d "${EXPORT_TEMPLATES_DIR}" ]; then
+    echo "Telechargement des modeles d'export Godot ${GODOT_VERSION} (environ 1,2 Go)..."
+    TMP_TPZ="$(mktemp)"
+    TMP_DIR="$(mktemp -d)"
+    curl -sL -o "${TMP_TPZ}" \
+        "https://github.com/godotengine/godot/releases/download/${GODOT_VERSION}/Godot_v${GODOT_VERSION}_export_templates.tpz"
+    unzip -q "${TMP_TPZ}" -d "${TMP_DIR}"
+    mkdir -p "${EXPORT_TEMPLATES_DIR}"
+    cp -r "${TMP_DIR}"/templates/* "${EXPORT_TEMPLATES_DIR}/"
+    rm -rf "${TMP_TPZ}" "${TMP_DIR}"
+else
+    echo "Modeles d'export deja presents dans ${EXPORT_TEMPLATES_DIR}."
+fi
+
 if [ ! -d "addons/gut" ]; then
     echo "Telechargement de GUT ${GUT_VERSION}..."
     TMP_TAR="$(mktemp)"