Edit files using a structured patch format.

Patch format:
- Must start with `*** Begin Patch` and end with `*** End Patch`.
- Supported file operations:
  - `*** Add File: <path>` followed by `+` lines.
  - `*** Delete File: <path>`.
  - `*** Update File: <path>` with one or more `@@` chunks.
  - Optional `*** Move to: <new_path>` after `*** Update File:`.
- Accepted update chunk headers:
  - `@@`
  - `@@ <existing source line>`
  - `@@ -a,b +c,d @@`
- Chunk body lines use prefixes: space (context), `-` (remove), `+` (add).
- Optional `*** End of File` anchor is supported inside update chunks.
- Do not use git file headers like `--- a/file` or `+++ b/file`.

Valid update example:
*** Begin Patch
*** Update File: hello.py
@@ -1,3 +1,4 @@
 import sys
+import logging
 
 def main():
*** End Patch

Use this tool when making targeted file edits from diff-like instructions.
For edits to existing files, this is the preferred tool over filesystem write.
Use `code_read` or `grep` first when you need more context before preparing the patch.
