Editor support generalized: shared core, language server, Vim and VS Code (from dev eb5baf9cbe59)

doc/edit/ now holds a shared Python implementation of the language's
structural layer (klammertext_edit.py) and a dependency-free language
server (klammertext_ls.py), with integrations for Emacs, Sublime Text,
Vim, and Visual Studio Code.  The editor test suite in tst/ covers the
core's API and CLI, the language server protocol, the VS Code
extension, headless Vim, and Emacs byte-equality.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

doc/edit/vscode/README.md

@@ -0,0 +1,100 @@
+# Klammertext support for Visual Studio Code
+
+VS Code support for editing Klammertext files (`.kt` documents and `.k`
+klammer definitions): syntax highlighting, delimiter matching and jumping,
+structural reindentation, table alignment, and delimiter diagnostics in the
+Problems panel.
+
+The extension has **no npm dependencies and no build step**.  Highlighting
+is a TextMate grammar (converted from the Sublime Text syntax); everything
+structural comes from the **Klammertext language server**
+(`klammertext_ls.py`), a dependency-free Python process the extension
+spawns, which itself runs the shared editor core (`klammertext_edit.py`)
+used by the Sublime Text and Vim integrations.  One implementation of the
+language's structure, everywhere.
+
+## Requirements
+
+- VS Code 1.75 or later — a minimum, not a target: VS Code's monthly
+  releases count 1.75, 1.76, … (1.75 is from January 2023), so any
+  version from the last few years qualifies.
+- `python3` on `PATH` (or set `klammertext.pythonPath`); Klammertext itself
+  already requires Python.
+- The language server, found automatically in this order:
+  1. the `klammertext.serverPath` setting, if set;
+  2. `klammertext_ls.py` vendored next to `extension.js` (the layout the
+     Klammertext editing zip ships);
+  3. `../shared/klammertext_ls.py` relative to the extension directory (the
+     layout of the Klammertext repository — using the extension straight
+     from a checkout just works);
+  4. `$KLAMMERTEXT_HOME/doc/edit/shared/klammertext_ls.py`.
+
+## Install
+
+Copy this `vscode/` directory into your VS Code extensions folder:
+
+    cp -R vscode ~/.vscode/extensions/klammertext
+
+then restart VS Code (or run the **Developer: Reload Window** command).  If
+you copy the directory out of the Klammertext tree, also copy
+`shared/klammertext_ls.py` and `shared/klammertext_edit.py` into the copied
+folder — or set `klammertext.serverPath`.  The editing zip from the
+Klammertext website ships the vendored copies already in place.
+
+**Note:** `.kt` is also Kotlin's extension.  Stock VS Code has no Kotlin
+support built in, so there is no conflict out of the box; if you install a
+Kotlin extension, the two will contend for `.kt` and you can decide per
+file with the language-mode picker (or `files.associations`).
+
+## What you get
+
+**Syntax highlighting** — the same token classes as the Emacs, Sublime
+Text, and Vim support: text removal (`#`, `##`, nestable `#[ ... ]#`), the
+three `@`-tiers — application (`@`), definition (`@@`), system (`@@@`) —
+each as an opening (`@name`, one unit) or a close (`name@`, bare `@`),
+`^`-escapes, and verbatim `@code ... code@` interiors.  Colors come from
+your theme (applications as functions, definitions as types, system
+commands as keywords, removed text as comments).  To adopt the full
+Klammertext palette (application blue / definition green / system orange,
+opens bright and closes darker), add `editor.tokenColorCustomizations`
+rules for the `*.klammertext` scopes in your settings.
+
+**Diagnostics** — unclosed and mismatched delimiters appear in the
+Problems panel as you type.
+
+**Formatting** — **Format Document** / **Format Selection** reindent
+structurally (2 spaces per nesting level; bar runs and closing delimiters
+sit at their opener's column; `@document` content stays at the margin;
+verbatim `@code` interiors, `@eval` code, and removed text are never
+touched).  Reindentation is **explicit-only**: there is deliberately no
+format-on-type, because whitespace is content in Klammertext.
+
+**Delimiter matching** — with the cursor on an application delimiter, the
+matching delimiter highlights (occurrences highlighting); **Go to
+Definition** on a delimiter goes to its match.  Literal klammers match by
+name (`@code` ↔ `code@`) with their verbatim content opaque; everything
+else matches by depth.
+
+**Commands and keybindings** (when editing Klammertext):
+
+| Key | Command |
+|---|---|
+| `Ctrl+Alt+J` (`Cmd+Alt+J`) | Klammertext: Jump to Matching Delimiter |
+| `Ctrl+Alt+A` (`Cmd+Alt+A`) | Klammertext: Align Table |
+
+Table alignment pads the cells of the `@table` enclosing the cursor so the
+`|` separators line up, with the shared rules: rows end with `||`; a row
+with a cell over 30 characters or spanning lines is left untouched; beyond
+100 columns the command declines; bars inside a nested klammer are not
+separators; no whitespace is ever inserted inside a bar run.
+
+**Text removal toggling** — `Ctrl+/` toggles `#` line removal and
+`Shift+Alt+A` wraps the selection in `#[ ... ]#`, via the standard VS Code
+comment commands.
+
+## Settings
+
+| Setting | Meaning (default) |
+|---|---|
+| `klammertext.pythonPath` | Python interpreter for the server (`python3`) |
+| `klammertext.serverPath` | full path to `klammertext_ls.py` (auto-located) |