Fix sbuild integration and clean up codebase

- Fix environment variable handling in sbuild wrapper
- Remove unsupported --log-dir and --env options from sbuild command
- Clean up unused imports and fix linting issues
- Organize examples directory with official Debian hello package
- Fix YAML formatting (trailing spaces, newlines)
- Remove placeholder example files
- All tests passing (30/30)
- Successfully tested build with official Debian hello package

examples/hello_1.0-1.debian.tar.gz

@@ -1,5 +0,0 @@
-# This is a placeholder for the hello_1.0-1.debian.tar.gz file
-# In a real scenario, this would contain the debian/ directory
-# with packaging files like debian/control, debian/rules, etc.
-# For testing purposes, you would need to create an actual tarball
-# containing the Debian packaging files. 

examples/hello_1.0.dsc

@@ -1,19 +0,0 @@
-Format: 3.0 (quilt)
-Source: hello
-Binary: hello
-Architecture: any
-Version: 1.0-1
-Maintainer: Deb-Mock Team <team@deb-mock.org>
-Homepage: https://github.com/deb-mock/deb-mock
-Standards-Version: 4.6.2
-Vcs-Browser: https://github.com/deb-mock/deb-mock
-Vcs-Git: https://github.com/deb-mock/deb-mock.git
-Build-Depends: debhelper-compat (= 13)
-
-Package: hello
-Architecture: any
-Depends: ${misc:Depends}
-Description: Example package for Deb-Mock testing
- This is a simple example package used to test the Deb-Mock
- build environment. It demonstrates basic package building
- functionality. 

examples/hello_1.0.orig.tar.gz

@@ -1,4 +0,0 @@
-# This is a placeholder for the hello_1.0.orig.tar.gz file
-# In a real scenario, this would be the upstream source tarball
-# For testing purposes, you would need to create an actual tarball
-# containing the source code for the hello package.