Shortcuts to bar items from launcher

Thanks for the fantastic shell! Switching in from Omarchy and this has been an incredibly seamless experience so far.

## Feature Description
I have grown fond of 100% keyboard based navigation that Omarchy allows. In particular, their 'launcher' has shortcuts to all the system functions - such as power menu, WiFi, Bluetooth etc.

Would it be possible to extend the DMS launcher to do the same? Not yet very familiar with Go, but I can take a crack at it if this interests a large enough number of people.

A mock up UI made with nano banana (I would imagine this menu could be made visible by typing :, like / is used for search. vim style.):

Searched for duplicate issue, couldn't find any.

## Use Case
Keyboard navigation.

## Compositor

Is this feature specific to one compositor?

- [x] All compositors
- [ ] niri
- [ ] Hyprland
- [ ] dwl (MangoWC)
- [ ] sway

## Proposed Solution
Hook up the options to the `dms ipc` commands. Should be fairly simple.

## Alternatives/Existing Solutions
Could hypothetically use walker or rofi etc. but I'd really rather not.

No source file or test is named. Start by tracing the DMS launcher entry point and the existing `dms ipc` commands; clarify which system functions should appear, how the proposed `:` mode behaves, and how keyboard-only navigation should work across all compositors.

Written by the indexing model from the issue text.