Initial vault-plugin-secrets-netbox

Vault/OpenBao secrets engine that mints NetBox API tokens via
/api/users/tokens/. A single seeded admin token (config) mints short-lived,
per-user tokens (roles -> creds) whose NetBox expiry is aligned to the Vault
lease; revoke deletes the token, renew extends its expiry. config/rotate
reissues the seeded admin token. Handles NetBox 4.6 v2 tokens (Bearer
nbt_<key>.<secret>) and legacy v1. Unit tests against an httptest NetBox mock;
dual Vault/OpenBao RPMs via nfpm; tag-driven release to artifactapi.

Claude-Session: https://claude.ai/code/session_01JUoARVdmhxKQHyyyp1pxeT

.pre-commit-config.yaml

@@ -0,0 +1,15 @@
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v5.0.0
+    hooks:
+      - id: trailing-whitespace
+      - id: end-of-file-fixer
+      - id: check-yaml
+      - id: check-added-large-files
+
+  - repo: https://github.com/dnephin/pre-commit-golang
+    rev: v0.5.1
+    hooks:
+      - id: go-fmt
+      - id: go-vet
+      - id: go-mod-tidy