chore: add comments for tessl auto-generated content

Ignore AGENTS.md in git (auto-created by tessl install) and add
explanatory comment in CLAUDE.md for the tessl-managed section.

.gitignore

@@ -259,3 +259,6 @@ WARP.MD
 .mcp.json
 .tessl/
 tessl.json
+
+# Tessl auto-generates AGENTS.md on install; ignore to avoid cluttering git status
+AGENTS.md

CLAUDE.md

@@ -88,6 +88,10 @@ else:
 - Commit message body should be concise (1-2 sentences max)
 - PR titles should also use conventional format
 
+<!-- Section below is auto-generated by `tessl install` - do not edit manually -->
+
 # Agent Rules <!-- tessl-managed -->
 
 @.tessl/RULES.md follow the [instructions](.tessl/RULES.md)
+
+@AGENTS.md