Decouple non-UI CLI startup from config_ui

Stop aman.py from importing the GTK settings module at module load so version, init, bench, diagnostics, and top-level help can start without pulling in the UI stack.\n\nPromote PyGObject and python-xlib into main project dependencies, switch the documented source install surface to plain uv/pip commands, and teach the portable, deb, and Arch packaging flows to install filtered runtime requirements before the Aman wheel so they still rely on distro-provided GTK/X11 packages.\n\nAdd regression coverage for importing aman with config_ui blocked and for the portable bundle's new requirements payload, then rerun the focused CLI/diagnostics/portable tests plus py_compile.

packaging/arch/PKGBUILD.in

@@ -14,6 +14,25 @@ sha256sums=('__TARBALL_SHA256__')
 prepare() {
   cd "${srcdir}/aman-${pkgver}"
   python -m build --wheel
+  python - <<'PY'
+from pathlib import Path
+import re
+import tomllib
+
+project = tomllib.loads(Path("pyproject.toml").read_text(encoding="utf-8"))
+exclude = {"pygobject", "python-xlib"}
+dependencies = project.get("project", {}).get("dependencies", [])
+filtered = []
+for dependency in dependencies:
+    match = re.match(r"\s*([A-Za-z0-9_.-]+)", dependency)
+    if not match:
+        continue
+    name = match.group(1).lower().replace("_", "-")
+    if name in exclude:
+        continue
+    filtered.append(dependency.strip())
+Path("dist/runtime-requirements.txt").write_text("\n".join(filtered) + "\n", encoding="utf-8")
+PY
 }
 
 package() {
@@ -21,7 +40,8 @@ package() {
   install -dm755 "${pkgdir}/opt/aman"
   python -m venv --system-site-packages "${pkgdir}/opt/aman/venv"
   "${pkgdir}/opt/aman/venv/bin/python" -m pip install --upgrade pip
-  "${pkgdir}/opt/aman/venv/bin/python" -m pip install "dist/aman-${pkgver}-"*.whl
+  "${pkgdir}/opt/aman/venv/bin/python" -m pip install --requirement "dist/runtime-requirements.txt"
+  "${pkgdir}/opt/aman/venv/bin/python" -m pip install --no-deps "dist/aman-${pkgver}-"*.whl
 
   install -Dm755 /dev/stdin "${pkgdir}/usr/bin/aman" <<'EOF'
 #!/usr/bin/env bash