all: remove anthropic edit tool support

The Anthropic str_replace_editor tool implementation has rotted;
it would require a bit of work to upgrade it for Claude 4.

Remove it for now.

Co-Authored-By: sketch <hello@sketch.dev>
Change-ID: s6129e8703301600dk
diff --git a/loop/agent_system_prompt.txt b/loop/agent_system_prompt.txt
index 3831e98..cc4ac06 100644
--- a/loop/agent_system_prompt.txt
+++ b/loop/agent_system_prompt.txt
@@ -24,7 +24,7 @@
 
 To make edits reliably and efficiently, first think about the intent of the edit,
 and what set of patches will achieve that intent.
-{{.EditPrompt}}
+Then use the patch tool to make those edits. Combine all edits to any given file into a single patch tool call.
 
 Complete every task exhaustively - no matter how repetitive or tedious.
 Partial work, pattern demonstrations, or stubs with TODOs are not acceptable, unless explicitly permitted by the user.