Replace the idealised concentric-circle range rings with a realistic
per-HRRR-grid-cell reception map. For every 0.125° grid point within
the band's exceptional range, the estimator computes great-circle
distance, FSPL + atmospheric loss, and applies a cell-specific score
adjustment of (50 - score) * 0.3 dB — score 100 gives a 15 dB ducting
boost, score 0 a 15 dB penalty. Cells below the -145 dBm detection
floor are dropped.
The beacon map hook now renders each surviving cell as a 0.125°
filled rectangle with a tooltip showing tier, Rx dBm, distance, and
HRRR score, so the coverage footprint bulges where ducting conditions
are good and cuts off where they aren't, instead of being a perfect
circle. Falls back to score 50 for cells that don't have HRRR data
yet, so the plot is always useful.
Also fixes the prior all-grey-tiles regression by restoring an
explicit setView() at map creation and adding a post-mount
invalidateSize() for when the map is placed inside a flex container.