refactor: overhaul codewalker with improved parser and ignore logic

- Implement level-scoped .gitignore/.heroignore matching
- Rewrite directory walker to use new ignore matcher
- Replace filemap parser with robust header-based logic
- Support `FILE`, `FILECHANGE`, and legacy header formats
- Add extensive tests for new parsing and ignore features

lib/develop/codewalker/README.md

@@ -1,64 +0,0 @@
-# CodeWalker Module
-
-The CodeWalker module provides functionality to walk through directories and create a map of files with their content. It's particularly useful for processing code directories while respecting gitignore patterns.
-
-## Features
-
-- Walk through directories recursively
-- Respect gitignore patterns to exclude files
-- Store file content in memory
-- Export files back to a directory structure
-
-## Usage
-
-```v
-import freeflowuniverse.herolib.lib.lang.codewalker
-
-mut cw := codewalker.new('/tmp/adir')!
-
-// Get content of a specific file
-content := cw.filemap.get('path/to/file.txt')!
-
-// return output again
-cw.filemap.content()
-
-// Export all files to a destination directory
-cw.filemap.export('/tmp/exported_files')!
-
-```
-
-### format of filemap 
-
-## full files
-
-```
-
-text before will be ignored
-
-===FILE:filename===
-code
-===FILE:filename===
-code
-===END===
-
-text behind will be ignored
-
-```
-
-## files with changes
-
-```
-
-text before will be ignored
-
-===FILECHANGE:filename===
-code
-===FILECHANGE:filename===
-code
-===END===
-
-text behind will be ignored
-
-```
-
-FILECHANGE and FILE can be mixed, in FILE it means we have full content otherwise only changed content e.g. a method or s struct and then we need to use morph to change it