Add bat syntax for WAFER / Forth 2012

Ship tools/editor-support/bat/WAFER.sublime-syntax so any bat user
(including oked, which probes bat first) renders .fth files with
proper keyword colouring, including the WAFER extras CONSOLIDATE,
RANDOM, RND-SEED, and UTIME.

Keyword list derives from register_primitive/register_host_primitive
calls in crates/core/src/outer.rs plus the boot.fth definitions.
Internal underscore-prefixed words are deliberately omitted.

Install with `just install-syntax`.

Justfile

@@ -57,3 +57,9 @@ ci: fmt clippy deny test
 # Check compilation without running
 check:
     cargo check --workspace
+
+# Install bat syntax highlighting for WAFER / Forth
+install-syntax:
+    mkdir -p ~/.config/bat/syntaxes
+    cp tools/editor-support/bat/WAFER.sublime-syntax ~/.config/bat/syntaxes/
+    bat cache --build