[anthonyportugal]

Fixes the layout surprise behind "new windows open at the start": Super+T (switch_layout) walked all 14 mango layouts because circle_layout was never set, so a few presses landed on fair. Merge without squash.

Changes

• circle_layout=dwindle,tile,monocle, so Super+T cycles a short list and returns to dwindle in at most two presses. The help text now says what it cycles.
• Super+Shift+T opens a Fuzzel picker with every layout mmsg get layouts reports, marks the current one (●) and applies the choice to the current tag.
• Waybar 0.16's native mango/layout module sits next to the workspaces, with an icon per common layout. A click opens the picker and scrolling cycles like Super+T.
• jq is declared in the MangoWM desktop manifest because the picker needs it. A missing jq or an unexpected layout list now raises a notification instead of passing for a dismissed menu.

Review notes

• Breaking changes: none. Every layout is still reachable through the picker.
• Both scroll directions cycle forward, because mango has no "previous layout" dispatch.

Testing

• tests/smoke.sh passes locally; mango -p validates the config.
• layers/wm/mangowm/tests/session-smoke.sh covers:
  • the circle list, keybind, help and Waybar module;
  • the picker applying a choice, marking the current layout, doing nothing when dismissed, and reporting a missing jq.
• Mutations (applying the symbol instead of the name; the old quiet failure) fail the tests.