fix(bootstrap): switch to the dashboard node floor via nvm or fnm

The dashboard pins engines node >=24.14.1 with engine-strict, so make
bootstrap dies with EBADENGINE on any shell whose default node is older.
Wrap the npm install in scripts/with_dashboard_node.sh: it execs the
command as-is when node already meets the floor, otherwise activates the
.nvmrc version via nvm or fnm, and fails fast with install instructions
when neither manager exists

Makefile

@@ -75,7 +75,7 @@ install-dev:
 bootstrap:
 	$(UV) sync --inexact --frozen --extra proxy --group proxy-dev --group e2e-dev
 	$(UV_RUN) python scripts/prisma_generate_if_needed.py
-	cd ui/litellm-dashboard && npm install --no-audit --no-fund
+	cd ui/litellm-dashboard && ../../scripts/with_dashboard_node.sh npm install --no-audit --no-fund
 	@main_root=$$(git worktree list --porcelain | head -1 | sed 's/^worktree //'); \
 	if [ "$$main_root" != "$$(git rev-parse --show-toplevel)" ] && [ -f "$$main_root/.env" ] && [ ! -f .env ]; then \
 		cp "$$main_root/.env" .env && echo "bootstrap: copied .env from $$main_root"; \

scripts/with_dashboard_node.sh

@@ -0,0 +1,52 @@
+#!/usr/bin/env bash
+set -eu
+
+[ $# -gt 0 ] || { echo "usage: $0 <command> [args...]" >&2; exit 2; }
+
+repo_root=$(cd "$(dirname "$0")/.." && pwd)
+dashboard="$repo_root/ui/litellm-dashboard"
+floor=$(sed -n 's/.*"node": *">=\([0-9][0-9.]*\)".*/\1/p' "$dashboard/package.json")
+pinned=$(tr -d '[:space:]' < "$dashboard/.nvmrc")
+floor="${floor:-$pinned}"
+
+meets_floor() {
+    awk -v have="$1" -v need="$2" 'BEGIN {
+        split(have, h, "."); split(need, n, ".")
+        for (i = 1; i <= 3; i++) {
+            if (h[i] + 0 < n[i] + 0) exit 1
+            if (h[i] + 0 > n[i] + 0) exit 0
+        }
+    }'
+}
+
+current=$(node --version 2>/dev/null | tr -d 'v' || true)
+if [ -n "$current" ] && meets_floor "$current" "$floor"; then
+    exec "$@"
+fi
+
+nvm_script="${NVM_DIR:-$HOME/.nvm}/nvm.sh"
+if [ -r "$nvm_script" ]; then
+    echo "with_dashboard_node: node ${current:-missing} is below the dashboard floor $floor; switching to $pinned via nvm" >&2
+    set +eu
+    . "$nvm_script" --no-use
+    nvm install "$pinned" >&2
+    nvm use "$pinned" >&2
+    set -eu
+    exec "$@"
+fi
+
+if command -v fnm > /dev/null 2>&1; then
+    echo "with_dashboard_node: node ${current:-missing} is below the dashboard floor $floor; switching to $pinned via fnm" >&2
+    fnm install "$pinned" >&2
+    eval "$(fnm env)"
+    fnm use "$pinned" >&2
+    exec "$@"
+fi
+
+cat >&2 <<EOF
+with_dashboard_node: node ${current:-missing} does not meet ui/litellm-dashboard's engines floor (>= $floor) and neither nvm nor fnm is available to switch automatically.
+Fix it with one of:
+  - install nvm (https://github.com/nvm-sh/nvm) and re-run; it will pick up node $pinned for you
+  - or install/upgrade node yourself to >= $floor (e.g. brew install node), then re-run
+EOF
+exit 1

tests/test_litellm/test_with_dashboard_node.py

@@ -0,0 +1,106 @@
+import json
+import os
+import subprocess
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[2]
+SCRIPT = ROOT / "scripts" / "with_dashboard_node.sh"
+
+
+def _floor() -> str:
+    pkg = json.loads((ROOT / "ui" / "litellm-dashboard" / "package.json").read_text())
+    return pkg["engines"]["node"].removeprefix(">=")
+
+
+def _bump_major(version: str, delta: int) -> str:
+    major, minor, patch = version.split(".")
+    return f"{int(major) + delta}.{minor}.{patch}"
+
+
+def _fake_node(bin_dir: Path, version: str) -> Path:
+    bin_dir.mkdir(parents=True, exist_ok=True)
+    node = bin_dir / "node"
+    node.write_text(f'#!/bin/sh\necho "v{version}"\n')
+    node.chmod(0o755)
+    return bin_dir
+
+
+def _run(bin_dirs: list[Path], home: Path) -> subprocess.CompletedProcess[str]:
+    path = os.pathsep.join([*(str(b) for b in bin_dirs), "/usr/bin", "/bin"])
+    home.mkdir(parents=True, exist_ok=True)
+    return subprocess.run(
+        [str(SCRIPT), "sh", "-c", "node --version"],
+        capture_output=True,
+        text=True,
+        env={"PATH": path, "HOME": str(home)},
+    )
+
+
+def test_node_meeting_the_floor_runs_the_command_as_is(tmp_path):
+    bins = _fake_node(tmp_path / "bin", _floor())
+    proc = _run([bins], tmp_path / "home")
+    assert proc.returncode == 0, proc.stderr
+    assert proc.stdout.strip() == f"v{_floor()}"
+
+
+def test_node_above_the_floor_runs_the_command_as_is(tmp_path):
+    above = _bump_major(_floor(), 1)
+    bins = _fake_node(tmp_path / "bin", above)
+    proc = _run([bins], tmp_path / "home")
+    assert proc.returncode == 0, proc.stderr
+    assert proc.stdout.strip() == f"v{above}"
+
+
+def test_old_node_without_any_manager_fails_with_instructions(tmp_path):
+    bins = _fake_node(tmp_path / "bin", _bump_major(_floor(), -1))
+    proc = _run([bins], tmp_path / "home")
+    assert proc.returncode == 1
+    assert "does not meet" in proc.stderr
+    assert _floor() in proc.stderr
+    assert "nvm" in proc.stderr
+
+
+def test_missing_node_without_any_manager_fails_with_instructions(tmp_path):
+    proc = _run([], tmp_path / "home")
+    assert proc.returncode == 1
+    assert "missing" in proc.stderr
+
+
+def test_old_node_switches_via_nvm_when_present(tmp_path):
+    old = _fake_node(tmp_path / "old-bin", _bump_major(_floor(), -1))
+    new = _fake_node(tmp_path / "new-bin", "99.0.0")
+    home = tmp_path / "home"
+    nvm_dir = home / ".nvm"
+    nvm_dir.mkdir(parents=True)
+    (nvm_dir / "nvm.sh").write_text(
+        f'nvm() {{ [ "$1" = use ] && PATH="{new}:$PATH"; return 0; }}\n'
+    )
+    proc = _run([old], home)
+    assert proc.returncode == 0, proc.stderr
+    assert proc.stdout.strip() == "v99.0.0"
+    assert "via nvm" in proc.stderr
+
+
+def test_old_node_switches_via_fnm_when_nvm_is_absent(tmp_path):
+    old = _fake_node(tmp_path / "old-bin", _bump_major(_floor(), -1))
+    new = _fake_node(tmp_path / "new-bin", "99.0.0")
+    fnm = tmp_path / "old-bin" / "fnm"
+    fnm.write_text(
+        f'#!/bin/sh\n[ "$1" = env ] && echo \'export PATH="{new}:$PATH"\'\nexit 0\n'
+    )
+    fnm.chmod(0o755)
+    proc = _run([old], tmp_path / "home")
+    assert proc.returncode == 0, proc.stderr
+    assert proc.stdout.strip() == "v99.0.0"
+    assert "via fnm" in proc.stderr
+
+
+def test_no_command_is_a_usage_error(tmp_path):
+    proc = subprocess.run(
+        [str(SCRIPT)],
+        capture_output=True,
+        text=True,
+        env={"PATH": "/usr/bin:/bin", "HOME": str(tmp_path)},
+    )
+    assert proc.returncode == 2
+    assert "usage" in proc.stderr