feat: v0.2.0 - Performance optimization and distribution pipeline

- Implemented multi-threaded directory traversal using ignore::WalkParallel
- Added dynamic thread allocation for balanced CPU utilization
- Refactored core logic to single-pass, in-memory tree construction (O(N))
- Added --compare, --units, and --precision flags
- Established SCM-neutral distribution pipeline (Makefile, release.sh, Homebrew)
- Comprehensive updates to README.md, MANUAL.md, and CHANGELOG.md
- Decoupled from SCM-specific workflows

SHIPMENT.md

@@ -0,0 +1,56 @@
+# Project Release Process
+
+This document defines the process for versioning and distributing the `sized` project independently of the Git hosting provider (GitHub, GitLab, Gitea).
+
+## 1. Versioning and Tagging
+
+The project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html). 
+
+1.  Synchronize the version in `Cargo.toml`.
+2.  Update `CHANGELOG.md` with the release notes.
+3.  Commit and create a git tag:
+    ```bash
+    git tag -a v0.2.0 -m "Release v0.2.0"
+    ```
+
+## 2. Asset Generation
+
+The `scripts/release.sh` script is the authoritative way to generate release assets locally or in any CI environment. 
+
+```bash
+./scripts/release.sh
+```
+
+This script generates:
+-   **Optimized Binary**: The production-ready `sized` executable.
+-   **Documentation**: The `sized.1` man page.
+-   **Shell Completions**: Scripts for Bash, Zsh, and Fish.
+-   **System Installers**: A `.deb` package for Debian-based Linux distributions.
+
+All assets are gathered in the `dist/v<VERSION>/` directory.
+
+## 3. Distribution Channels
+
+### crates.io
+To update the project on the central Rust registry:
+```bash
+cargo publish
+```
+
+### System Package Managers
+For Homebrew, GitLab, or Gitea-based distribution:
+1.  Push the git tag to your SCM.
+2.  Run the release script to generate assets.
+3.  Attach the contents of the `dist/` folder to your SCM's "Release" or "Tag" entry.
+4.  Update downstream formulas (like `homebrew-tap`) with the new source URL and SHA256 of the generated tarball.
+
+## 4. Automation & Hooks
+
+To automate asset generation locally, you can use a git `post-checkout` or a wrapper script. Since gitea and gitlab use different CI formats, it is recommended to simply call `./scripts/release.sh` within your preferred CI runner (e.g., `gitlab-ci.yml` or `gitea-actions`).
+
+## 5. Manual Installation
+For system-wide installation from source, use the `Makefile`:
+```bash
+make install
+```
+Defaults to `PREFIX=/usr/local`. Overridable via `PREFIX=/your/path make install`.