step 2: init command + SQLite storage + migrations + config

- storage.go: DB wrapper, migration runner (in-code SQL strings)
- migrations.go: 001_init (nodes + node_meta + indexes)
- vault.go: Init() creates .verstak/ dirs, config.yml, index.db
- config.go: YAML config read/write
- util/uuid.go: UUIDv7 generator
- cmd/verstak/main.go: init --vault PATH command
- main_test.go: TestInitCreatesVault, TestInitConfigYAML

Acceptance: go build ./... pass, go test ./... pass
Init creates test-vault with .verstak/index.db + config.yml
Repeat Init is safe.

docs/PLAN.md

@@ -11,7 +11,7 @@
 
 | # | Шаг | Статус |
 |---|-----|--------|
-| 1 | Git init + Skeleton | ⬜ не начат |
+| 1 | Git init + Skeleton | ✅ выполнен |
 | 2 | Init + SQLite + First Migration | ⬜ не начат |
 | 3 | Nodes Repository + CRUD + CLI Node | ⬜ не начат |
 | 4 | Vault Files: Trash + File Service + CLI File | ⬜ не начат |