Initial commit: NexusOS project + desktop theme baseline

Captures the known-good state after theme consolidation and
consistency reconciliation:
- NexusOS GTK/xfwm4/icon theme assets (assets/themes, management/Mint-Y-Nexus)
- Tightened right-click menus, visible separators, no menu icons
- assets/themes/install-theme.sh: idempotent restore of all wiring
  (symlinks, xfconf xsettings+xfwm4, GTK 3/4 settings.ini)
- .gitignore excludes venv/ollama/models/runtime/db

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

assets/boot/my-custom-logo/my-custom-logo.plymouth

@@ -0,0 +1,54 @@
+[Plymouth Theme]
+Name=My Custom Logo
+Description=Custom boot logo with shimmer effect
+ModuleName=two-step
+
+[two-step]
+Font=Cantarell 12
+TitleFont=Cantarell Light 30
+ImageDir=/usr/share/plymouth/themes/my-custom-logo
+DialogHorizontalAlignment=.5
+DialogVerticalAlignment=.382
+TitleHorizontalAlignment=.5
+TitleVerticalAlignment=.382
+HorizontalAlignment=.5
+VerticalAlignment=.5
+WatermarkHorizontalAlignment=.5
+WatermarkVerticalAlignment=.96
+Transition=none
+TransitionDuration=0.0
+BackgroundStartColor=0x000000
+BackgroundEndColor=0x000000
+ProgressBarBackgroundColor=0x606060
+ProgressBarForegroundColor=0xffffff
+MessageBelowAnimation=true
+
+[boot-up]
+UseEndAnimation=false
+
+[shutdown]
+UseEndAnimation=false
+
+[reboot]
+UseEndAnimation=false
+
+[updates]
+SuppressMessages=true
+ProgressBarShowPercentComplete=true
+UseProgressBar=true
+Title=Installing Updates...
+SubTitle=Do not turn off your computer
+
+[system-upgrade]
+SuppressMessages=true
+ProgressBarShowPercentComplete=true
+UseProgressBar=true
+Title=Upgrading System...
+SubTitle=Do not turn off your computer
+
+[firmware-upgrade]
+SuppressMessages=true
+ProgressBarShowPercentComplete=true
+UseProgressBar=true
+Title=Upgrading Firmware...
+SubTitle=Do not turn off your computer