refactor(voidbox): split CLI into modules and add snapshot subcommands

.github/workflows/ci.yml

@@ -159,10 +159,10 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - name: Install Rust 1.85
+      - name: Install Rust 1.88
         uses: dtolnay/rust-toolchain@master
         with:
-          toolchain: "1.85"
+          toolchain: "1.88"
 
       - name: Check build with MSRV
         run: |

AGENTS.md

@@ -154,11 +154,14 @@ pipeline and won't carry trace context or attributes.
 | `.warn()` | Partial failures, degraded conditions |
 | `.error()` | Step/workflow failures |
 
-**CLI subscriber:** `src/bin/voidbox.rs` initializes `tracing_subscriber` with
-`EnvFilter` defaulting to `"info"`. Override at runtime with:
+**CLI subscriber:** `src/bin/voidbox/main.rs` initializes `tracing_subscriber` with
+`EnvFilter` from the resolved log level (see `src/bin/voidbox/cli_config.rs` for merge order).
+Override at runtime with `VOIDBOX_LOG_LEVEL` or `--log-level`, or set `RUST_LOG` when no explicit
+CLI/config level is set:
 
 ```bash
-RUST_LOG=debug cargo run --bin voidbox -- run --file spec.yaml
+VOIDBOX_LOG_LEVEL=debug cargo run --bin voidbox -- run --file spec.yaml
+# RUST_LOG also applies when VOIDBOX_LOG_LEVEL / config omit log_level
 ```
 
 **Convention:** Workflow progress messages use the `[workflow:<name>]` prefix
@@ -171,7 +174,8 @@ pattern, e.g. `[workflow:my-flow] step 1/3: "build" running...`.
 | `src/observe/logs.rs` | `StructuredLogger`, `LogConfig`, `LogEntry`, `LogLevel` |
 | `src/observe/mod.rs` | `Observer` (owns logger), `SpanGuard` (RAII span + logging) |
 | `src/workflow/scheduler.rs` | Step progress logging via `observer.logger()` |
-| `src/bin/voidbox.rs` | CLI `tracing_subscriber` + `EnvFilter` setup |
+| `src/bin/voidbox/main.rs` | CLI `tracing_subscriber` + `EnvFilter` setup |
+| `src/bin/voidbox/cli_config.rs` | CLI config merge (`VOIDBOX_*`, YAML, `--log-level`) |
 
 ### Key source files
 

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Changed
+- Rust MSRV bumped to 1.88
+
 ## [0.1.2] - 2026-03-16
 
 ### Added

CONTRIBUTING.md

@@ -230,7 +230,7 @@ void-box/
 │   ├── lib.rs              # Main library entry point
 │   ├── artifacts.rs        # Artifact management
 │   ├── bin/
-│   │   └── voidbox.rs      # CLI tool
+│   │   └── voidbox/        # CLI tool
 │   ├── sandbox/            # Sandbox abstraction
 │   ├── workflow/           # Workflow engine
 │   ├── observe/            # Observability layer