feat: v0.2.0 optimization refactor and docs

- Refactor core traversal to single-pass O(N) tree construction
- Optimize CSV output using `csv` crate for robust escaping
- Optimize JSON output with zero-copy serialization
- Add MANUAL.md
- Bump version to 0.2.0
- Remove walkdir dependency

Cargo.toml

@@ -1,11 +1,11 @@
 [package]
 name = "sized"
-version = "0.1.0"
+version = "0.2.0"
 edition = "2021"
 
 [dependencies]
 clap = { version = "4.4", features = ["derive"] }
-walkdir = "2.3"
+
 rayon = "1.8"
 humansize = "2.1"
 colored = "2.0"
@@ -19,3 +19,4 @@ csv = "1.3"
 chrono = "0.4"
 clap_complete = "4.4"
 atty = "0.2"
+clap_mangen = "0.2.31"