feat(config): codegraph.json include to force gitignored first-party source into the index (#1063)

Adds an `include` list to the root `codegraph.json` that forces gitignored first-party source (second-VCS / SVN / Perforce dual-tracked repos) into the index — discovered directly off disk on the full index, incremental sync, and file-watching, on both git and non-git projects. Gitignore-style patterns, root-relative; explicit `exclude` still wins and built-in skips (node_modules, dist, .git) are never re-included. Complements `exclude` and `includeIgnored`.

Closes #1163.

Thanks @luoyxy for the contribution.

README.md

@@ -686,6 +686,21 @@ watch:
 }
 ```
 
+Conversely, when real source is gitignored on purpose — a project under a second
+VCS (SVN, Perforce) that `.gitignore`s its own source so it stays out of Git —
+force it back in with `include` (the opposite of `exclude`; `includeIgnored`
+only revives embedded git repos, not plain source):
+
+```json
+{
+  "include": ["Tools/", "Local/typescript/"]
+}
+```
+
+CodeGraph discovers those files off disk, overriding `.gitignore`, on index,
+sync, and watch. An explicit `exclude` still wins, and built-in skips
+(`node_modules`, `dist`, `.git`) are never re-included.
+
 ### Custom file extensions
 
 If your project uses a non-standard extension for a [supported