v0.2: Pico-8 Lua dialect grammar and language

Reorganize into grammars/<name>/ subdirs ( Zed's [grammars.*] supports
a `path` field, so both grammars ship from this repo without a sibling-
repo split ). Vendor tree-sitter-lua as the fork base for tree-sitter-
pico8-lua; upstream MIT license preserved at grammars/pico-8-lua/
UPSTREAM-LICENSE.md.

Dialect features added: != as ~= alias, \ integer divide, ^^ binary xor,
>>> / <<> / >>< shifts and rotates, compound-assignment statements,
memory peek prefixes @ % $ (% coexists with binary modulo), single-line
`if (cond) stmt [else stmt]` and `while (cond) stmt`, statement-level
print shorthand ?, and `#include path` directives. Identifier rule no
longer accepts ! ? @ $ ( upstream did ).

Pico-8 Lua language ( languages/pico-8-lua/, suffix .p8lua ) ships
highlights with the full ~110 PICO-8 builtins as @function.builtin.
The cart injection now hands __lua__ bodies to pico-8-lua, so .p8 carts
and bare .p8lua files share the dialect-aware grammar. Examples updated
to exercise the dialect end-to-end.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

languages/pico-8-lua/indents.scm

@@ -0,0 +1,20 @@
+; Indent inside any block-bearing construct.
+(do_statement) @indent
+(while_statement) @indent
+(repeat_statement) @indent
+(for_statement) @indent
+(if_statement) @indent
+(elseif_statement) @indent
+(else_statement) @indent
+(function_declaration) @indent
+(function_definition) @indent
+(table_constructor) @indent
+(parenthesized_expression) @indent
+(arguments) @indent
+
+; The closing keywords/brackets sit at the parent's indent level.
+"end" @end
+"until" @end
+"}" @end
+")" @end
+"]" @end