Rename project: ubuntu-fido -> authforge

Renames the package and all artifacts to authforge to drop the
distro-specific prefix, since the roadmap targets Ubuntu + Debian +
KDE + eventually Fedora (option C in the design).

- deb packages: authforge, authforge-{daemon,pam,cli,gui,gnome-integration}
- binaries: authforged, authforgectl, authforge (GUI)
- D-Bus name: io.dangerousthings.AuthForge
- PAM module: pam_authforge_pending.so
- Paths: /etc/authforge/, /var/lib/authforge/, /usr/share/pam-configs/authforge
- PPA: ppa:dangerousthings/authforge

Filesystem path /home/work/VSCodeProjects/ubuntu_fido/ left as-is for
historical reference; can rename later via git mv at the dir level.

Verified: cargo build/test/clippy/fmt clean, pam builds, gui builds,
all 5 debs produced.

debian/copyright

@@ -1,7 +1,7 @@
 Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
-Upstream-Name: ubuntu-fido
+Upstream-Name: authforge
 Upstream-Contact: Dangerous Things <ops@dangerousthings.com>
-Source: https://github.com/dangerousthings/ubuntu-fido
+Source: https://github.com/dangerousthings/authforge
 
 Files: *
 Copyright: 2026 Dangerous Things, LLC