Archive add-ghostty-gnome-tweaks-dark-mode, sync specs

Ghostty, the GNOME Tweaks gating requirement, and the GNOME dark-mode
default were already implemented and committed; this syncs the
delta specs into openspec/specs/desktop-applications and
openspec/specs/gnome-desktop and moves the change to archive/.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HngxrvqEzq8oBEBDtrYJyB

1 files changed, 12 insertions, 1 deletions

diff --git a/openspec/specs/desktop-applications/spec.md b/openspec/specs/desktop-applications/spec.md
index 8758177..ec5e7fe 100644
--- a/openspec/specs/desktop-applications/spec.md
+++ b/openspec/specs/desktop-applications/spec.md
@@ -7,7 +7,7 @@ Provisions everyday desktop GUI applications (chat, communication, and music cli
 ## Requirements
 
 ### Requirement: Desktop GUI applications are provisioned via the shared home profile
-The shared home-manager profile SHALL include Slack, Discord, Spotify, teams-for-linux, Firefox, and the Bitwarden desktop client as GUI application packages, available wherever that profile is activated and the underlying package supports the current system.
+The shared home-manager profile SHALL include Slack, Discord, Spotify, teams-for-linux, Firefox, the Bitwarden desktop client, and Ghostty as GUI application packages, available wherever that profile is activated and the underlying package supports the current system. GNOME Tweaks is provisioned per the separate requirement below, since its availability depends on GNOME being enabled rather than on platform support alone.
 
 #### Scenario: GUI app available after activation
 - **WHEN** the shared home profile is activated on a system for which a given desktop application's package is supported
@@ -26,3 +26,14 @@ teams-for-linux SHALL be provisioned only on Linux systems, consistent with its
 #### Scenario: Excluded on a non-Linux system
 - **WHEN** the shared home profile is activated on a non-Linux system
 - **THEN** teams-for-linux is not included in the provisioned package set
+
+### Requirement: GNOME Tweaks is provisioned only where GNOME is enabled
+GNOME Tweaks SHALL be included in the provisioned package set only where the GNOME desktop is enabled (every NixOS host built from this flake's shared system module), and SHALL be excluded wherever GNOME is not known to be enabled, including standalone (non-NixOS) home-manager activations of the shared profile.
+
+#### Scenario: Included on a NixOS host with GNOME enabled
+- **WHEN** the shared home profile is activated as part of a NixOS host built from this flake's shared system module, where GNOME is enabled
+- **THEN** GNOME Tweaks is included in the provisioned package set
+
+#### Scenario: Excluded on a standalone activation
+- **WHEN** the shared home profile is activated standalone, not as part of a NixOS system (for example via `home-manager switch` on a non-NixOS machine)
+- **THEN** GNOME Tweaks is not included in the provisioned package set, regardless of the host's operating system