fix(nvim,remote-dev): fall back to PATH node + provide JRE/shellharden/python3-venv

copilot.lua was hard-coding the chezmoi-pinned Node 24 at
~/.local/share/copilot-node/bin/node, which only exists on the Arch
host where chezmoi runs run_onchange_after_install-copilot-node.sh.
On the remote-dev VM the path is absent, so copilot-language-server
spawned with cmd[0]=<missing> and printed 'Could not determine
Node.js version'. Probe the pinned path with vim.fn.executable() and
fall back to 'node' from PATH otherwise.

For the VM PATH 'node' to be a supported version, switch home.nix
from the rolling 'nodejs' alias to 'nodejs_24' (the version the
chezmoi script also pins on the host).

Address the cluster of Mason install failures on the VM:
  - autotools-language-server, codespell, mdformat,
    nginx-language-server, systemdlint -- pip-installed; fail because
    Ubuntu's python3 ships without venv. bootstrap.sh now apt-installs
    python3-venv; README documents the manual command for existing VMs.
  - groovy-language-server -- needs a JRE. Add 'jre' to home.packages.
  - shellharden -- Mason's cargo fallback can't run under our
    leaf-tools policy. Provide the binary via nix-profile instead so
    Mason finds it on PATH.

1 files changed, 13 insertions, 6 deletions

diff --git a/dot_config/nvim/lua/plugins/ai.lua b/dot_config/nvim/lua/plugins/ai.lua
index 6578037..6ebc6f5 100644
--- a/dot_config/nvim/lua/plugins/ai.lua
+++ b/dot_config/nvim/lua/plugins/ai.lua
@@ -1,12 +1,19 @@
+-- Prefer the chezmoi-pinned Node 24 (host has Arch's system node 26, which
+-- breaks copilot-language-server — see
+-- ~/.local/share/chezmoi/run_onchange_after_install-copilot-node.sh). Fall
+-- back to `node` on PATH for hosts that don't run chezmoi (remote-dev VM
+-- via Nix Home-Manager, where home.nix pins nodejs_24 in the profile).
+local pinned_node = vim.fs.joinpath(
+  vim.env.XDG_DATA_HOME or (vim.env.HOME .. "/.local/share"),
+  "copilot-node/bin/node"
+)
+local copilot_node = vim.fn.executable(pinned_node) == 1 and pinned_node
+  or "node"
+
 require("copilot").setup({
   suggestion = { enabled = false },
   panel = { enabled = false },
-  -- Pinned Node 24 runtime; system nodejs (26.x) is incompatible with
-  -- copilot-language-server. See ~/.local/share/chezmoi/run_onchange_after_install-copilot-node.sh
-  copilot_node_command = vim.fs.joinpath(
-    vim.env.XDG_DATA_HOME or (vim.env.HOME .. "/.local/share"),
-    "copilot-node/bin/node"
-  ),
+  copilot_node_command = copilot_node,
   server_opts_overrides = {
     settings = {
       telemetry = {