Add collage hero and update TUI guide screen layout

Collage of all 5 screens as hero image below the intro.
Updated screen names and descriptions to match the current
4-tab layout (Dashboard, Control, Signal, System + Console).
Fresh screenshots from demo mode replace the originals.

src/content/docs/guides/tui.mdx

@@ -12,6 +12,8 @@ import { Aside, Steps, Tabs, TabItem } from '@astrojs/starlight/components';
 
 Mission control for less than dinner for two.
 
+![Birdcage TUI — all screens shown in demo mode](/screenshots/tui-collage.png)
+
 Somewhere inside every Winegard Carryout G2 is a 2013-vintage NXP Cortex-M4 running firmware 02.02.48,
 driving two Allegro A3981 stepper motors and a Broadcom BCM4515 DVB-S2 tuner through 12 submenus
 and over 100 undocumented commands. In 2026, it takes commands from a Python TUI built on
@@ -54,64 +56,63 @@ does something. You don't need a dish on the roof to try it.
 
 ## Five Screens
 
-Navigate between screens with **F1**–**F5** keys or click the sidebar buttons.
+Navigate between screens with **F1**–**F5** keys or click the tab bar at the top.
 The device status bar at the bottom persists across all screens — connection state,
 serial port, firmware version, and current menu prompt are always visible.
 
-### F1 — Position
+### F1 — Dashboard
 
-![Birdcage TUI Position screen showing compass rose, AZ/EL readout, and sparkline history](/screenshots/tui-position.png)
+![Birdcage TUI Dashboard screen showing action cards for dish operations](/screenshots/tui-dashboard.png)
 
-The position screen is where you point the dish. A compass rose shows current azimuth
-with a bearing indicator, while AZ and EL sparklines track movement history over time.
-The numeric readout at top shows position to hundredths of a degree — the G2's stepper
-resolution is 0.009° azimuth (40,000 steps/rev) and 0.014° elevation (24,960 steps/rev).
+The launch pad. Four action cards — **Point Dish**, **Monitor Signal**, **Scan Sky**, and
+**Stow** — each jump to the relevant screen with a single click. It's the screen you see
+on connect, and the one you come back to when you're done adjusting.
 
-The AZ and EL sparklines give you immediate visual feedback: flat lines mean the dish
-is parked, slopes mean it's slewing, and the amplitude of the noise floor after arrival
-tells you how much stepper backlash you're dealing with.
+### F2 — Control
 
-### F2 — Signal
+![Birdcage TUI Control screen showing compass rose, step size selector, and manual controls](/screenshots/tui-control.png)
+
+Where you actually point the dish. Three modes across the top: **Manual**, **Presets**, and **Track**.
+
+In Manual mode, a compass rose shows current azimuth with a bearing indicator. AZ and EL
+readouts update live — the G2's stepper resolution is 0.009° azimuth (40,000 steps/rev)
+and 0.014° elevation (24,960 steps/rev). Arrow keys nudge the dish, with a step size
+selector (0.1° to 10°) that multiplies each keypress. AZ and EL sparklines give immediate
+visual feedback: flat lines mean the dish is parked, slopes mean it's slewing, and the noise
+floor after arrival tells you how much stepper backlash you're dealing with.
+
+Below the sparklines, velocity controls let you tune motor speed on the fly — set AZ and EL
+max velocity in °/s and hit Apply. The firmware stores these in STEP> as microsteps/sec,
+but the TUI handles the conversion. Home AZ, Home EL, and E/R (engage/release motors)
+round out the bottom toolbar.
+
+### F3 — Signal
 
 ![Birdcage TUI Signal screen showing RSSI gauge, DVB and ADC sparklines](/screenshots/tui-signal.png)
 
 Signal strength from two sources: the BCM4515 DVB tuner's RSSI (bounded, averaged)
-and the raw ADC reading (single-shot). The gauge uses sub-character Unicode block elements
-(▏▎▍▌▋▊▉█) for smooth visual resolution. Below the gauge, DVB RSSI and ADC RSSI
-sparklines show signal trends over time — useful for peaking during manual dish adjustment.
+and the raw ADC reading (single-shot). Three modes: **Monitor** (live gauges), **Sweep**
+(automated peaking), and **Sky Map** (2D RSSI heatmap from `azscanwxp` scans).
 
-The sample counter and iteration display at bottom track measurement throughput. On a
-live dish with the LNA enabled (`lnbdc odu`), you'll see the noise floor sit around
-RSSI 500 (ADC) or 230–490 (DVB, polarity-dependent).
-
-### F3 — Scan
-
-The scan screen wraps the firmware's `azscanwxp` command — Davidson's radio telescope
-mode. Define an AZ×EL grid, set the step resolution, and watch the sky heatmap fill
-in with RSSI-colored cells as the dish sweeps. Results export to CSV for post-processing
-into proper sky maps.
-
-<Aside>
-No screenshot for this one yet — the scan screen needs a live dish or a long-running demo
-sweep to produce interesting output. It exists, it works, and it's waiting for first light.
-</Aside>
+In Monitor mode, the gauge uses sub-character Unicode block elements (▏▎▍▌▋▊▉█) for
+smooth visual resolution. The Receiver panel alongside shows tuner frequency, symbol rate,
+LNB voltage/polarity, lock status, and SNR. On a live dish with the LNA enabled
+(`lnbdc odu`), the noise floor sits around RSSI 500 (ADC) or 230–490 (DVB, polarity-dependent).
 
 ### F4 — System
 
-![Birdcage TUI System screen showing firmware ID, A3981 diagnostics, motor dynamics, and NVS table](/screenshots/tui-system.png)
+![Birdcage TUI System screen showing firmware ID, A3981 diagnostics, and motor dynamics](/screenshots/tui-system.png)
 
-The system dashboard. Top row shows the firmware identity banner: version 02.02.48,
-K60 MCU at 96 MHz, antenna ID "12-IN G2". Below that, two side-by-side panels:
+The system dashboard with three tabs: **Hardware**, **Motors**, and **NVS Config**.
 
-- **A3981 Diagnostics** — fault pin status for both stepper drivers (AZ/EL DIAG: OK or FAULT),
-  plus step size mode (AUTO means the driver handles microstepping transitions automatically).
-- **Motor Dynamics** — max velocity and acceleration for each axis. The G2 defaults to
-  65.0°/s azimuth, 45.0°/s elevation, with 400.0°/s² acceleration — fast enough to track
-  LEO satellites at medium altitudes.
+The Hardware tab shows the firmware identity banner — version 02.02.48, K60 MCU at 96 MHz,
+antenna ID "12-IN G2" — and A3981 stepper driver diagnostics: fault pin status for both
+drivers (AZ/EL DIAG: OK or FAULT), step size mode (AUTO means the driver handles
+microstepping transitions automatically), and current control mode.
 
-The NVS Table at the bottom is a scrollable browser of all 134 non-volatile storage values.
-Current, saved, and default columns let you see what's been modified. The "Refresh NVS"
-and "Export NVS JSON" buttons at the bottom do what you'd expect.
+The NVS Config tab provides a scrollable browser of all 134 non-volatile storage values.
+Current, saved, and default columns let you see what's been modified. Refresh and Export
+buttons at the bottom do what you'd expect.
 
 ### F5 — Console