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.
Replace Leaflet/raster tiles with MapLibre GL JS: an online OpenFreeMap
style and an offline style built from a local PMTiles archive via
pmtiles.js and protomaps-themes-base (no glyphs/labels offline by
design, see docs/architecture.adoc). Frontend libraries are vendored
locally rather than loaded from a CDN so the app keeps working with no
internet access.
Also add an animated RainViewer precipitation radar overlay (toggle,
play/pause, scrub slider), matching the default time window of the
weather-radar-card Home Assistant integration.