feat: first-draft preview-capable zosstorage

- CLI: add topology selection (-t/--topology), preview flags (--show/--report), and removable policy override (--allow-removable) (src/cli/args.rs)
- Config: built-in sensible defaults; deterministic overlays for logging, fstab, removable, topology (src/config/loader.rs)
- Device: discovery via /proc + /sys with include/exclude regex and removable policy (src/device/discovery.rs)
- Idempotency: detection via blkid; safe emptiness checks (src/idempotency/mod.rs)
- Partition: topology-driven planning (Single, DualIndependent, BtrfsRaid1, SsdHddBcachefs) (src/partition/plan.rs)
- FS: planning + creation (mkfs.vfat, mkfs.btrfs, bcachefs format) and UUID capture via blkid (src/fs/plan.rs)
- Orchestrator: pre-flight with preview JSON (disks, partition_plan, filesystems_planned, mount scheme). Skips emptiness in preview; supports stdout+file (src/orchestrator/run.rs)
- Util/Logging/Types/Errors: process execution, tracing, shared types (src/util/mod.rs, src/logging/mod.rs, src/types.rs, src/errors.rs)
- Docs: add README with exhaustive usage and preview JSON shape (README.md)

Builds and unit tests pass: discovery, util, idempotency helpers, and fs parser tests.

Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "zosstorage"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+anyhow = "1.0.100"
+base64 = "0.22.1"
+clap = { version = "4.5.48", features = ["derive"] }
+nix = "0.30.1"
+regex = "1.11.3"
+serde = { version = "1.0.227", features = ["derive"] }
+serde_json = "1.0.145"
+serde_yaml = "0.9.33"
+tempfile = "3.23.0"
+thiserror = "2.0.16"
+time = "0.3.44"
+humantime = "2.1.0"
+tracing = "0.1.41"
+tracing-subscriber = "0.3.20"
+uuid = "1.18.1"
+which = "8.0.0"