Keep git-lfs's own hooks, now that the hook path is ours

`core.hooksPath` points at `.githooks` for the traceability hook, and that
redirects *every* hook — including the four git-lfs installs for itself. They
were written there by `git lfs install` and left untracked, which is the worst
of both: present for whoever ran it, absent for everyone else.

`pre-push` is the one that matters. It is what uploads LFS objects, so without
it a push can land a pointer on the server with nothing behind it — which is
exactly the failure CI has been hitting from the other side, and not a state to
risk creating by accident.

Committed rather than regenerated per clone, because `git lfs install` writes
to `.git/hooks` by default and would miss the redirect entirely.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

.githooks/post-checkout

@@ -0,0 +1,3 @@
+#!/bin/sh
+command -v git-lfs >/dev/null 2>&1 || { printf >&2 "\n%s\n\n" "This repository is configured for Git LFS but 'git-lfs' was not found on your path. If you no longer wish to use Git LFS, remove this hook by deleting the 'post-checkout' file in the hooks directory (set by 'core.hookspath'; usually '.git/hooks')."; exit 2; }
+git lfs post-checkout "$@"

.githooks/post-commit

@@ -0,0 +1,3 @@
+#!/bin/sh
+command -v git-lfs >/dev/null 2>&1 || { printf >&2 "\n%s\n\n" "This repository is configured for Git LFS but 'git-lfs' was not found on your path. If you no longer wish to use Git LFS, remove this hook by deleting the 'post-commit' file in the hooks directory (set by 'core.hookspath'; usually '.git/hooks')."; exit 2; }
+git lfs post-commit "$@"

.githooks/post-merge

@@ -0,0 +1,3 @@
+#!/bin/sh
+command -v git-lfs >/dev/null 2>&1 || { printf >&2 "\n%s\n\n" "This repository is configured for Git LFS but 'git-lfs' was not found on your path. If you no longer wish to use Git LFS, remove this hook by deleting the 'post-merge' file in the hooks directory (set by 'core.hookspath'; usually '.git/hooks')."; exit 2; }
+git lfs post-merge "$@"

.githooks/pre-push

@@ -0,0 +1,3 @@
+#!/bin/sh
+command -v git-lfs >/dev/null 2>&1 || { printf >&2 "\n%s\n\n" "This repository is configured for Git LFS but 'git-lfs' was not found on your path. If you no longer wish to use Git LFS, remove this hook by deleting the 'pre-push' file in the hooks directory (set by 'core.hookspath'; usually '.git/hooks')."; exit 2; }
+git lfs pre-push "$@"