feat(noctalia): add knowledge lookup panel

Provide a portable, cache-ignored Obsidian vault lookup plugin and bind it to Super+N.

.config/noctalia/90-machine.toml##class.arch_desktop

@@ -1,7 +1,7 @@
 # Desktop-specific shell layout and hardware telemetry.
 # Pi Status Bridge is installed locally from ~/projects/pi-gui.
 [plugins]
-enabled = ["alex/system-status", "alex/pi-status-bridge"]
+enabled = ["alex/system-status", "alex/pi-status-bridge", "alex/knowledge-lookup"]
 
 [widget.pi-status]
 type = "alex/pi-status-bridge:bridge"