ci: gate pushes on a gitleaks scan of the outgoing commits

No repo here scanned for committed credentials. The hook is self-contained
rather than delegating to a Makefile, because this repo has none and a hook
reaching into a sibling repo breaks the moment this one is cloned elsewhere.

Scans the outgoing range rather than full history: history carries settled
findings — test fixtures, vendored third-party code — and a gate that fails
on something unfixable gets bypassed within a week.

Setting core.hooksPath means pql init must replant its replication shims into
.githooks, which is why they are gitignored here alongside the tracked
pre-push. Same layout pql itself uses.

Co-Authored-By: Claude <noreply@anthropic.com>

.gitignore

@@ -92,3 +92,11 @@ task-data/
 .claude/settings.local.json
 .pql/*
 !.pql/changelog/
+
+# pql shims planted by `pql init` into the dir core.hooksPath points at.
+# Per-clone: each embeds the absolute path of the pql binary that planted it.
+# Only .githooks/pre-push is shared.
+.githooks/pre-commit
+.githooks/post-merge
+.githooks/post-checkout
+.githooks/post-rewrite