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historical reference; can rename later via git mv at the dir level.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.

gui/data/io.dangerousthings.AuthForge.svg

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" width="64" height="64" viewBox="0 0 64 64">
+  <!-- Placeholder icon: a simple key glyph. Replace with branded asset before release. -->
+  <g fill="none" stroke="#3584e4" stroke-width="3" stroke-linecap="round" stroke-linejoin="round">
+    <circle cx="22" cy="32" r="9"/>
+    <path d="M31 32h22"/>
+    <path d="M44 32v8"/>
+    <path d="M52 32v6"/>
+  </g>
+</svg>