chore: drop tool-name markers from source comments

Seventeen comments opened with a tag naming the tool that wrote them.
The tag goes and each comment keeps its reasoning, now starting as a
plain sentence. None of the reasoning changes.

The AGENTS.md note in .gitignore drops the story of how the file got
into the tree and keeps the one fact a reader needs: its advice to run
go fmt is destructive on this CRLF working tree.

Comments only; no code, build or test changes.

.gitignore

@@ -41,9 +41,8 @@ plugins/*/bin/
 
 # ---- Local agent / loop state ----
 .claude/
-# Autohand-generated agent guide — kept on disk for local tooling, never tracked.
-# It rode in via 0c1cc59, claims precedence over CLAUDE.md, and tells agents to
-# run `go fmt` (destructive on this CRLF working tree).
+# Generated tooling guide, kept on disk for local use and never tracked. Its advice
+# to run `go fmt` is destructive on this CRLF working tree.
 AGENTS.md
 
 # ---- Internal planning & design docs (excluded from the public remote per