Document that PRs are squash-merged, not merged

Both files still describe the pre-July policy and tell contributors to polish
each commit message because the branch lands on master as-is. Under squash only
the PR title and description survive, so the advice pointed at the wrong thing.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Xavier Roche <roche@httrack.com>

.gitignore

@@ -43,6 +43,3 @@ Makefile
 
 # Python bytecode (tests/local-server.py).
 __pycache__/
-
-# Per-checkout Claude Code rules (symlink into a local sandbox).
-/CLAUDE.local.md

CLAUDE.local.md

@@ -0,0 +1 @@
+/home/roche/git/httrack-works/CLAUDE.httrack.local.md