editors syntax highlighting ...

- emacs syntax: add tree-sitter major mode for SiSU spine markup
  New file sisu-spine-ts-mode.el is a sibling of the existing regex
  mode, backed by Emacs 29+'s built-in treesit.el and the
  tree-sitter-sisu grammar. It replaces the long font-lock keyword list
  with treesit-font-lock-rules grouped into eight features (comment,
  header, heading, block, inline, note, link, index, misc) so users
  can dial verbosity via treesit-font-lock-level. It also wires up:
  - treesit-simple-imenu-settings for a heading outline,
  - treesit-thing-settings for sentence / paragraph motions,
  - treesit-defun-type-regexp so C-M-a / C-M-e jump heading-to-heading,
  - a sisu-spine-ts-install-grammar command that registers
    treesit-language-source-alist and runs
    treesit-install-language-grammar so users can install the parser
    from inside Emacs without leaving the editor.

- the original sisu-spine-mode.el is unchanged and supported for
  Emacs < 29 and for users who prefer regex highlighting.

- nvim drop-in: point parser fetch at tools/tree-sitter-sisu
  sundry/editor-syntax-etc/nvim/
  The nvim-treesitter install_info now fetches the parser from
  https://git.sisudoc.org/projects/tree-sitter-sisu which can be cloned
  via git://git.sisudoc.org/tools/tree-sitter-sisu The fetched paths:
    files = { "src/parser.c", "src/scanner.c" }
  submission of the sisu parser to nvim-treesitter's parsers.lua should
  be a near-trivial one-liner.

- the original vim regex highlighter remains as before
  - sundry/editor-syntax-etc/vim/syntax/sisu-spine.vim
  - sundry/editor-syntax-etc/vim/templates/{sst,ssm,ssi}.tpl
    new skeleton templates for the three SiSU markup file types
    sets up the YAML header (title, creator, date, rights, classify,
    identfier)

- .gitignore - whitelist the new files

(assisted by Claude-Code)

1 files changed, 87 insertions, 0 deletions

diff --git a/sundry/editor-syntax-etc/nvim/README.md b/sundry/editor-syntax-etc/nvim/README.md
new file mode 100644
index 0000000..8e889e7
--- /dev/null
+++ b/sundry/editor-syntax-etc/nvim/README.md
@@ -0,0 +1,87 @@
+# Neovim integration for SiSU spine markup
+
+Tree-sitter-backed syntax highlighting, folding, and structural
+navigation for `.sst` / `.ssm` / `.ssi` files in Neovim (>= 0.9).
+
+## What is in this directory
+
+```
+nvim/
+  ftdetect/sisu.lua        - register .sst/.ssm/.ssi as filetype "sisu"
+  ftplugin/sisu.lua        - per-buffer settings (commentstring, conceal)
+  lua/sisu-spine/init.lua  - entry point: registers parser config
+  queries/sisu/            - tree-sitter queries (mirrors tree-sitter-sisu/queries/)
+    highlights.scm
+    folds.scm
+    injections.scm
+    textobjects.scm
+    indents.scm
+```
+
+## Install (manual)
+
+1. Symlink or copy this directory into your Neovim runtime path:
+
+   ```sh
+   ln -s /path/to/sisudoc-spine/sundry/editor-syntax-etc/nvim \
+         ~/.config/nvim/pack/sisu/start/sisu-spine
+   ```
+
+2. Tell `nvim-treesitter` how to fetch the parser. Add to your config
+   (`init.lua`):
+
+   ```lua
+   require("sisu-spine").setup()
+   require("nvim-treesitter.configs").setup({
+     ensure_installed = { "sisu" },
+     highlight       = { enable = true },
+     indent          = { enable = true },
+     fold            = { enable = true },
+     textobjects     = { select = { enable = true, lookahead = true } },
+   })
+   ```
+
+3. Build the parser:
+
+   ```vim
+   :TSInstall sisu
+   ```
+
+That is it. Open a `.sst` file - highlighting, folding, and textobject
+selection should all work.
+
+## Install (lazy.nvim)
+
+```lua
+{
+  dir = "/path/to/sisudoc-spine/sundry/editor-syntax-etc/nvim",
+  name = "sisu-spine",
+  ft = { "sisu" },
+  dependencies = { "nvim-treesitter/nvim-treesitter" },
+  config = function()
+    require("sisu-spine").setup()
+  end,
+}
+```
+
+## Sync queries from upstream
+
+The query files are duplicated from `tree-sitter-sisu/queries/` so that
+this Neovim drop-in works without depending on the parser repo's
+checkout layout. To refresh them after grammar changes:
+
+```sh
+cp ../../../sisudoc-spine-tools/tree-sitter-sisu/queries/*.scm \
+   queries/sisu/
+```
+
+(Path is relative to this README.)
+
+## Upstreaming the parser
+
+When the parser is publicly hosted under a stable URL it is worth
+submitting a config to `nvim-treesitter` so users can run `:TSInstall
+sisu` without the local `setup()` call. The required fields are in
+`lua/sisu-spine/init.lua` (`install_info` table); send a PR to
+<https://github.com/nvim-treesitter/nvim-treesitter> patching
+`lua/nvim-treesitter/parsers.lua`.