feat(zig): include .zig/.zon in default scan + CHANGELOG entry

Adds **/*.zig and **/*.zon to DEFAULT_CONFIG.include so the CLI
picks up Zig sources without manual config. Documents the new
language support and the comptime-type limitation in CHANGELOG.

https://claude.ai/code/session_017AQjdPam3enwct9vFi4G1S

Author: claude

CHANGELOG.md

@@ -7,6 +7,22 @@ a [GitHub Release](https://github.com/colbymchenry/codegraph/releases) tagged
 This project follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/)
 and adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased] - 2026-05-16
+
+### Added
+- Zig language support (Zig 0.16+). Indexes `.zig` and `.zon` files using
+  `tree-sitter-zig`. Extracts structs and their methods, enums and members,
+  error sets (modelled as enums), `@import` calls (as `import` nodes with
+  `imports` references), `pub` visibility, plain constants/variables, and
+  `test "..." { ... }` blocks as functions.
+
+### Known limitations
+- Comptime-generated types such as
+  `fn Physics(comptime R: type) type { return struct { ... }; }`
+  are not resolvable at the tree-sitter level — full type inference would be
+  required. Methods defined on such types are not extracted. This is
+  documented at the top of `src/extraction/languages/zig.ts`.
+
 ## [0.7.6] - 2026-05-13
 
 ### Fixed

src/types.ts

@@ -546,6 +546,9 @@ export const DEFAULT_CONFIG: CodeGraphConfig = {
     // Scala
     '**/*.scala',
     '**/*.sc',
+    // Zig
+    '**/*.zig',
+    '**/*.zon',
   ],
   exclude: [
     // Version control