Apply DD recommendations: complete conversion to debhelper files

• Simplify debian/rules to minimal overrides only
• Convert installation to .install, .links, .manpages files
• Remove manual copyright installation (handled by debhelper)
• Remove unnecessary maintainer scripts (postinst/postrm)
• Add debian/README.Debian for end users
• Fix binary installation to prevent subdir-in-usr-bin error

NOTES: I have pushed the upstream and pristine-tar branches, so: gbp integration will be completed after the packaging improvements in this MR are approved and merged.

My original packaging was done in a single branch with upstream + Debian mixed together.

Your suggested gbp workflow (Arturo) requires restructuring that should happen after approval. Post-Approval Plan After the MR is approved:

Start fresh with proper gbp structure Apply the approved changes. Proper gbp import: Set up upstream/pristine-tar correctly