feat: complete Rust port of claude-statusline

Port the entire 2236-line bash statusline script to Rust.
Implements all 25 sections, 3-phase layout engine (render, priority
drop, flex/justify), file-based caching with flock, 9-level terminal
width detection, trend sparklines, and deep-merge JSON config.

Release binary: 864K with LTO. Render time: <1ms warm.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Cargo.toml

@@ -0,0 +1,37 @@
+[package]
+name = "claude-statusline"
+version = "0.1.0"
+edition = "2021"
+description = "Fast, configurable status line for Claude Code"
+license = "MIT"
+repository = "https://github.com/tayloreernisse/claude-statusline"
+
+[[bin]]
+name = "claude-statusline"
+path = "src/bin/claude-statusline.rs"
+
+[lib]
+name = "claude_statusline"
+path = "src/lib.rs"
+
+[dependencies]
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+md-5 = "0.10"
+unicode-width = "0.2"
+unicode-segmentation = "1"
+libc = "0.2"
+serde_path_to_error = "0.1"
+serde_ignored = "0.1"
+
+[dev-dependencies]
+criterion = { version = "0.5", features = ["html_reports"] }
+
+[[bench]]
+name = "render"
+harness = false
+
+[profile.release]
+lto = true
+codegen-units = 1
+strip = true