fix: nvim first boot on a fresh box — tree-sitter CLI, no luarocks, guarded local plugin

nvim-treesitter (main) hard-requires the tree-sitter CLI: new manifest
row via npm. hererocks failed compiling lua 5.1 (readline headers) for
oxocarbon's incidental rockspec: rocks disabled, the colorscheme works
without. The ~/code/nvim-ai-assist local plugin gets a cond so boxes
without the checkout skip it silently. All three found live, phase 5 VM.

dot_local/share/dotup/packages.tsv

@@ -30,6 +30,7 @@
 @needs	agents/pi-plugins	agents/pi
 @needs	agents/specify-cli	core/uv
 @needs	core/mermaid-cli	core/node
+@needs	core/tree-sitter	core/node
 # The three rows with no apt package at all. They resolved to brew and
 # nothing installed brew, so `^a` ticked them and they failed on every
 # fresh Linux box. On Linux brew lives entirely under
@@ -47,6 +48,7 @@
 @spec	agents/pi-plugins	@juicesharp/rpiv-ask-user-question @juicesharp/rpiv-btw @juicesharp/rpiv-todo @samfp/pi-memory @tmustier/pi-ralph-wiggum pi-markdown-preview pi-powerline-footer pi-simplify pi-subagents pi-web-access
 @spec	agents/specify-cli	specify-cli
 @spec	core/mermaid-cli	@mermaid-js/mermaid-cli
+@spec	core/tree-sitter	tree-sitter-cli
 @spec	core/bitwarden-cli	bw
 @spec	apps/obsidian	md.obsidian.Obsidian
 @spec	apps/chrome	https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb
@@ -69,6 +71,7 @@ core	brew	safe	-script	-builtin	linuxbrew — the only source for lazygit, omp a
 core	node	safe	-tarball	node	apt ships 18.19 and the npm rows below need 20+ — tarball to /opt/node
 core	imagemagick	safe	imagemagick	imagemagick	required by the nvim markdown render path
 core	mermaid-cli	safe	-npm	-npm	mmdc — nvim renders mermaid fences with it
+core	tree-sitter	safe	-npm	-npm	tree-sitter CLI — nvim-treesitter (main) refuses to start without it
 core	btop	safe	btop	btop
 core	htop	safe	htop	htop
 core	ncdu	safe	ncdu	ncdu