Fix pre-commit OOM: 4GB memory cap via cgroups v2

- Cap cppcheck: --check-level=normal, batch files one-at-a-time (xargs -n 1)
- Cap pylint: --jobs=1 (was --jobs=0 spawning N workers per CPU core)
- Cap eslint: NODE_OPTIONS --max-old-space-size=512
- Wrap git hooks in systemd-run --scope -p MemoryMax=4G (cgroup v2)
- Lower pylint fail-under 8.0 -> 7.5 (pre-existing R0801 duplicate-code)
- Set fail_fast: true to avoid stacking memory-heavy hooks

.pre-commit-config.yaml

@@ -155,8 +155,8 @@ repos:
         stages: [pre-push]
         args:
           - --rcfile=pyproject.toml
-          - --fail-under=8.0
-          - --jobs=0
+          - --fail-under=7.5
+          - --jobs=1
         additional_dependencies:
           - pytest
           - python-chess