feat(firstboot): идемпотентный provision /data + machine-id (A06)

lib provision (idempotent; factory-reset; recover mid-run) + bin; machine-id из /dev/urandom.
Привязка к /etc/machine-id — every-boot юнит (План 5). Дефолты настроек — Settings.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Signed-off-by: Alexander <akotenev2003@gmail.com>

crates/core/shturman-firstboot/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "shturman-firstboot"
+version = "0.0.0"
+edition.workspace = true
+license.workspace = true
+
+[dependencies]
+shturman-common = { path = "../../shturman-common" }
+anyhow.workspace = true
+tracing.workspace = true
+
+[dev-dependencies]
+tempfile.workspace = true