Baseline: Ludic compiler + toolchain, Phase 1 syntax fixes complete

Self-hosted compiler (selfhost/*.ludic), runtime, examples, editor tooling,
and docs. Phase 1 of the syntax-redesign cohesion pass has landed:
edge-system fix, signature-query, when-alias, and the documentation truth-pass.
Suite green (14/14), C-free bootstrap fixpoint holds.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tools/editors/zed/README.md

@@ -0,0 +1,39 @@
+# Ludic for Zed
+
+Zed extensions want a Tree-sitter grammar for highlighting, which this toolchain
+deliberately does not ship — the vocabulary lives in one C header and is exposed
+through the language server's semantic tokens instead, so there is no second
+grammar to keep honest.
+
+That is enough for Zed: point it at `ludic-lsp` and highlighting, completion,
+diagnostics and formatting all arrive over LSP.
+
+Add to `~/.config/zed/settings.json`:
+
+```json
+{
+  "lsp": {
+    "ludic-lsp": {
+      "binary": { "path": "/path/to/gpp/build/ludic-lsp", "arguments": ["--stdio"] },
+      "initialization_options": {
+        "compilerPath": "/path/to/gpp/build/ludicc",
+        "compilerDiagnostics": true,
+        "indentSize": 2
+      }
+    }
+  },
+  "file_types": { "Ludic": ["ludic"] },
+  "languages": {
+    "Ludic": {
+      "language_servers": ["ludic-lsp"],
+      "tab_size": 2,
+      "hard_tabs": false,
+      "format_on_save": "on"
+    }
+  }
+}
+```
+
+If you would rather have static highlighting too, the TextMate grammar in
+`tools/editors/shared/ludic.tmLanguage.json` can be dropped into a Zed extension
+that declares a `grammars` entry — but it is not required.