0.8.0 - Keychron V0 Ultra numpad Support

• The Keychron V0 Ultra numpad. A new surface, verified on two boards. M1–M5 are lanes 1–5, one key per agent — dim, breathing, double-pulsing, full, dark red — and the four shape keys are a top line showing one agent in the F-row's patterns. The knob picks which agent the top line shows: unlocked it follows whatever changed last; press it to lock, and the M key fades to white and back. Pressing an M key selects that agent and brings its window forward; the top line's four keys bring the shown agent forward, and while it is Waiting the three after the first answer Up, Down and Enter — sent, as everywhere, only into a terminal that verifiably has the keyboard. Over the cable or the 2.4 GHz receiver, on the protocol the Ultra already speaks; the app takes nine LEDs and leaves the rest of the board alone, and two Keychrons on one bus sort themselves out. Setup, once: the same per-key-brightness firmware fix built for the V0 (firmware/keychron-ultra, ./build.sh keychron_v0_ultra_ansi), and the keymap as a file — the Launcher cannot enter a chord — Keymap tab, Export yours first, then Import firmware/keychron-ultra/keymaps/keychron_v0_ultra_ansi.json over the cable.
• Preview drives the numpad. With a Preview playing every M key is lit, so the knob steps across all five and an M key selects; the cursor and the lock can be seen before any agent is there. When the preview ends the cursor falls back to a real agent.
• Lanes speak per device. The "no keys" tag on lanes 4–6 is gone — the numpad carries five. The caption above the lanes, the lane-count picker, each lane's number and the Focus button say where a lane has keys: the F-row three, the numpad five, a deck one per row, the window and mini mode all of them.
• Devices lines name their keys. "Keychron V3 Ultra 8K over USB: the F-row, 3 lanes of 4 keys", like the deck's "3 lanes of 5 keys" and the numpad's "the four shape keys and M1–M5". A device that is not there says "not detected"; iCUE running but refusing says what to turn on.
• Smaller: agent-frow doctor has a "V0 Ultra:" section; the numpad's snapshot is its own file and can never cross-restore the keyboard's.

Upgrade: unzip, run once, delete the folder. Nothing to restart — hooks and the status line are unchanged since 0.7.0. The numpad needs its firmware and keymap once; the README says how.