[BUG] Desktop RPM package name `opencode` collides with the openSUSE `opencode` CLI package — zypper/Discover offer to replace Desktop with the CLI

Bug description

The Desktop app's RPM package is named opencode, which collides with the
CLI package opencode that ships in the openSUSE Tumbleweed repositories.
As a result, on openSUSE (and any distro that ships an opencode CLI package),
package managers (zypper / Discover via PackageKit) see the installed Desktop
RPM as a "different/older version" of the CLI and offer to replace the Desktop
app with the CLI binary.

Steps to reproduce

1. Install OpenCode Desktop from https://opencode.ai/download/stable/linux-x64-rpm
   on openSUSE Tumbleweed.
2. Run zypper se -s opencode — two different products share the same RPM name:
   • i+ opencode 1.18.20-1 (Pacchetti di sistema) ← the Desktop RPM just installed
   • v opencode 1.18.18-1.1 (repo-oss) ← the CLI from the openSUSE repo
3. Run sudo zypper dup — zypper reports a "problem" and offers to replace the
   installed Desktop app (vendor "OpenCode") with the openSUSE CLI package.
   Discover also shows a fake "upgrade".

Expected behavior

The Desktop app should use a distinct package name (e.g. opencode-desktop or
ai.opencode.desktop) so it cannot be confused with, or replaced by, the CLI
package. The two products should coexist without conflicts.

Actual behavior

• rpm -q opencode on the Desktop install reports:

  Name        : opencode
  Version     : 1.18.20
  Vendor      : OpenCode <hello@opencode.ai>
  Source RPM  : opencode-1.18.20-1.src.rpm
  

  and installs Desktop files to /opt/OpenCode/ (ai.opencode.desktop,
  ai.opencode.desktop.desktop, opencode-desktop.desktop).
• The openSUSE repo provides a separate opencode CLI package (1.18.18-1.1)
  that zypper treats as a conflicting version of the same package.

Environment

• OS: openSUSE Tumbleweed (20260819)
• Desktop RPM version: 1.18.20-1 (installed from the official site)
• Package manager: zypper / libzypp, GNOME Discover (PackageKit)

Notes

Related existing issues: #15827, #15829, #9273, #7666. This one is specific to
distributions that ship an official opencode CLI package (openSUSE), where the
name collision causes the package manager to offer replacing Desktop with the CLI.