feat: Implement comprehensive Debian packaging improvements and enhanced CI workflow

- Enhanced Package Information: Expanded PackageInfo struct with 23 fields including section, priority, maintainer, homepage, size, dependencies, and more
- Real Package Data Extraction: Integrated dpkg and apt-cache for actual package information instead of mock data
- Professional Debian Packaging: Added man pages, shell completions, postinst/prerm scripts, triggers, and lintian overrides
- Enhanced Build System: Improved debian/rules with cross-compilation support, enhanced build.sh with options and validation
- CI Workflow Updates: Added missing build dependencies, enhanced package validation, lintian quality checks, and comprehensive reporting
- Quality Assurance: Added lintian validation, enhanced file checking, and professional packaging standards
- Documentation: Comprehensive README.Debian with build instructions and troubleshooting guide

Resolves mock package issues and provides production-ready Debian packaging infrastructure.

debian/rules

@@ -6,27 +6,75 @@
 # This has to be exported to make some magic below work.
 export DH_OPTIONS
 
-# Build system
+# Build system configuration
 export CARGO_HOME = $(CURDIR)/debian/cargo
 export CARGO_TARGET_DIR = $(CURDIR)/debian/cargo/target
 
+# Detect architecture for cross-compilation
+DEB_HOST_ARCH ?= $(shell dpkg-architecture -qDEB_HOST_ARCH)
+DEB_BUILD_ARCH ?= $(shell dpkg-architecture -qDEB_BUILD_ARCH)
+
+# Rust target for cross-compilation
+RUST_TARGET := $(shell dpkg-architecture -qDEB_HOST_ARCH_GNU_TYPE)
+
+# Build flags
+CARGO_FLAGS := --release
+ifneq ($(DEB_HOST_ARCH),$(DEB_BUILD_ARCH))
+    CARGO_FLAGS += --target $(RUST_TARGET)
+endif
+
 override_dh_auto_build:
-	# Build apt-ostree with cargo - ensure rustup environment is available
-	export PATH=$(HOME)/.cargo/bin:$$PATH
-	cargo build --release
+	@echo "Building apt-ostree for $(DEB_HOST_ARCH)..."
+	# Ensure cargo is available
+	@which cargo > /dev/null || (echo "Error: cargo not found. Please install Rust toolchain." && exit 1)
+	# Build apt-ostree with cargo
+	cargo build $(CARGO_FLAGS)
 	dh_auto_build
 
 override_dh_auto_install:
+	@echo "Installing apt-ostree binary..."
 	# Install the apt-ostree binary to the correct location
-	install -D -m 755 debian/cargo/target/release/apt-ostree debian/apt-ostree/usr/bin/apt-ostree
-	# Create any additional directories or files needed
+	install -D -m 755 debian/cargo/target/$(if $(filter $(DEB_HOST_ARCH),$(DEB_BUILD_ARCH)),release,$(RUST_TARGET)/release)/apt-ostree \
+		debian/apt-ostree/usr/bin/apt-ostree
+	# Create additional directories
 	mkdir -p debian/apt-ostree/usr/share/doc/apt-ostree
+	mkdir -p debian/apt-ostree/usr/share/man/man1
+	mkdir -p debian/apt-ostree/usr/share/bash-completion/completions
+	mkdir -p debian/apt-ostree/usr/share/zsh/vendor-completions
+	# Install man page if it exists
+	@if [ -f "debian/apt-ostree.1" ]; then \
+		install -D -m 644 debian/apt-ostree.1 debian/apt-ostree/usr/share/man/man1/apt-ostree.1; \
+	fi
+	# Install bash completion if it exists
+	@if [ -f "debian/apt-ostree.bash-completion" ]; then \
+		install -D -m 644 debian/apt-ostree.bash-completion \
+			debian/apt-ostree/usr/share/bash-completion/completions/apt-ostree; \
+	fi
+	# Install zsh completion if it exists
+	@if [ -f "debian/apt-ostree.zsh-completion" ]; then \
+		install -D -m 644 debian/apt-ostree.zsh-completion \
+			debian/apt-ostree/usr/share/zsh/vendor-completions/_apt-ostree; \
+	fi
 	# Skip dh_auto_install since we've handled installation manually
 
 override_dh_auto_clean:
+	@echo "Cleaning cargo build artifacts..."
 	# Clean cargo build artifacts
 	rm -rf debian/cargo
 	dh_auto_clean
 
+override_dh_strip:
+	# Strip debug symbols from binary
+	dh_strip --dbg-package=apt-ostree-dbg
+	# Keep debug package for development
+
+override_dh_shlibdeps:
+	# Handle shared library dependencies
+	dh_shlibdeps
+
+override_dh_fixperms:
+	# Fix file permissions
+	dh_fixperms
+
 %:
 	dh $@