Drop the OsmAnd-recolor map theme, add offline labels and a lighter palette nudge

Remove osmand-style.js (the per-layer color-patching approach) and its
docs entirely — back to the plain OpenFreeMap "liberty" style online,
and protomaps-themes-base's stock theme offline as the base.

Offline maps previously had no text labels at all: the
protomaps-themes-base layers() call never passed a lang option, which
is required to include its label layers. Fixed, backed by vendored
Noto Sans Regular/Italic/Medium glyph PBFs (ranges 0-255 and 256-511
only — Basic Latin + Latin-1 Supplement + Latin Extended-A, enough for
accented Central European place names; other scripts won't render
offline). Verified against the actual offline.pmtiles vector layer
schema that the name/name:en/script fields this expects are present.

Also nudge a handful of OFFLINE_THEME color roles (background, water,
wood, buildings, the two road-importance tiers) towards the online
style's actual palette (sampled from its style JSON) so switching
Online/Offline doesn't look like two different apps — deliberately
partial, not the removed full recolor.

README.adoc

@@ -10,8 +10,7 @@ The project's shape is still open — this is the initial scaffold.
 == Status
 
 Early scaffold. The web application serves a vector map (MapLibre GL
-JS), styled to resemble https://osmand.net/map[OsmAnd's own map], with
-an online style and an optional offline style backed by a local
+JS), with an online style and an optional offline style backed by a local
 PMTiles file, an animated RainViewer radar overlay, GPX
 upload/display (points and tracks, organized in folders), and a live
 position marker from a local GNSS receiver via gpsd.