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

Makefile

@@ -0,0 +1,25 @@
+PREFIX ?= /usr/local
+BINDIR = $(PREFIX)/bin
+MANDIR = $(PREFIX)/share/man/man1
+
+.PHONY: all build install clean help
+
+all: build
+
+build:
+	cargo build --release
+
+install: build
+	install -d $(BINDIR)
+	install -m 755 target/release/sized $(BINDIR)/sized
+	install -d $(MANDIR)
+	install -m 644 sized.1 $(MANDIR)/sized.1
+
+clean:
+	cargo clean
+
+help:
+	@echo "Usage:"
+	@echo "  make build    - Build the optimized binary"
+	@echo "  make install  - Install binary and man page (may require sudo)"
+	@echo "  make clean    - Remove build artifacts"