Replace offline basemap pipeline with Planetiler, unify online/offline styling

Offline tiles were built from Protomaps' own basemap schema, needing a
completely separate hand-tuned theme (protomaps-themes-base + OFFLINE_THEME)
from the online Liberty style's ONLINE_STYLE_PATCH — the two could never be
made to match exactly no matter how much either side got tuned (today's
session found and fixed several mismatches: building opacity, park
boundaries, road casings, road widths).

Offline.pmtiles is now built with Planetiler's default OpenMapTiles profile
against Geofabrik per-country OSM extracts (osmium-merged when more than one
country is selected), the same vector schema Liberty already expects.
offlineStyle() now clones the same Liberty JSON (vendored as a local
snapshot for reliability with no internet) and applies the identical
ONLINE_STYLE_PATCH, just repointed at local PMTiles/glyphs/sprite — one
palette instead of two, correct on both sides by construction.

Also vendors Liberty's icon sprite for the first time (offline had none
before), adds Java/osmium-tool/planetiler.jar to the Docker image, and
removes the now-unused protomaps-themes-base dependency and the
theme-comparison debug page that found today's bugs.

public/vendor/liberty-style/liberty.json

@@ -0,0 +1 @@
+{"version":8,"sources":{"ne2_shaded":{"maxzoom":6,"tileSize":256,"tiles":["https://tiles.openfreemap.org/natural_earth/ne2sr/{z}/{x}/{y}.png"],"type":"raster"},"openmaptiles":{"type":"vector","url":"https://tiles.openfreemap.org/planet"}},"sprite":"https://tiles.openfreemap.org/sprites/ofm_f384/ofm","glyphs":"https://tiles.openfreemap.org/fonts/{fontstack}/{range}.pbf","layers":[{"id":"background","type":"background","paint":{"background-color":"#f8f4f0"}},{"id":"natural_earth","type":"raster","source":"ne2_shaded","maxzoom":7,"paint":{"raster-opacity":["interpolate",["exponential",1.5],["zoom"],0,0.6,6,0.1]}},{"id":"park","type":"fill","source":"openmaptiles","source-layer":"park","paint":{"fill-color":"#d8e8c8","fill-opacity":0.7,"fill-outline-color":"rgba(95, 208, 100, 1)"}},{"id":"park_outline","type":"line","source":"openmaptiles","source-layer":"park","paint":{"line-color":"rgba(228, 241, 215, 1)","line-dasharray":[1,1.5]}},{"id":"landuse_residential","type":"fill","source":"openmaptiles","source-layer":"landuse","maxzoom":12,"filter":["==",["get","class"],"residential"],"paint":{"fill-color":["interpolate",["linear"],["zoom"],9,"hsla(0,3%,85%,0.84)",12,"hsla(35,57%,88%,0.49)"]}},{"id":"landcover_wood","type":"fill","source":"openmaptiles","source-layer":"landcover","filter":["==",["get","class"],"wood"],"paint":{"fill-antialias":false,"fill-color":"hsla(98,61%,72%,0.7)","fill-opacity":0.4}},{"id":"landcover_grass","type":"fill","source":"openmaptiles","source-layer":"landcover","filter":["==",["get","class"],"grass"],"paint":{"fill-antialias":false,"fill-color":"rgba(176, 213, 154, 1)","fill-opacity":0.3}},{"id":"landcover_ice","type":"fill","source":"openmaptiles","source-layer":"landcover","filter":["==",["get","class"],"ice"],"paint":{"fill-antialias":false,"fill-color":"rgba(224, 236, 236, 1)","fill-opacity":0.8}},{"id":"landcover_wetland","type":"fill","source":"openmaptiles","source-layer":"landcover","minzoom":12,"filter":["==",["get","class"],"wetland"],"paint":{"fill-antialias":true,"fill-opacity":0.8,"fill-pattern":"wetland_bg_11","fill-translate-anchor":"map"}},{"id":"landuse_pitch","type":"fill","source":"openmaptiles","source-layer":"landuse","filter":["==",["get","class"],"pitch"],"paint":{"fill-color":"#DEE3CD"}},{"id":"landuse_track","type":"fill","source":"openmaptiles","source-layer":"landuse","filter":["==",["get","class"],"track"],"paint":{"fill-color":"#DEE3CD"}},{"id":"landuse_cemetery","type":"fill","source":"openmaptiles","source-layer":"landuse","filter":["==",["get","class"],"cemetery"],"paint":{"fill-color":"hsl(75,37%,81%)"}},{"id":"landuse_hospital","type":"fill","source":"openmaptiles","source-layer":"landuse","filter":["==",["get","class"],"hospital"],"paint":{"fill-color":"#fde"}},{"id":"landuse_school","type":"fill","source":"openmaptiles","source-layer":"landuse","filter":["==",["get","class"],"school"],"paint":{"fill-color":"rgb(236,238,204)"}},{"id":"waterway_tunnel","type":"line","source":"openmaptiles","source-layer":"waterway","filter":["==",["get","brunnel"],"tunnel"],"paint":{"line-color":"#a0c8f0","line-dasharray":[3,3],"line-gap-width":["interpolate",["linear"],["zoom"],12,0,20,6],"line-opacity":1,"line-width":["interpolate",["exponential",1.4],["zoom"],8,1,20,2]}},{"id":"waterway_river","type":"line","source":"openmaptiles","source-layer":"waterway","filter":["all",["==",["get","class"],"river"],["!=",["get","brunnel"],"tunnel"]],"layout":{"line-cap":"round"},"paint":{"line-color":"#a0c8f0","line-width":["interpolate",["exponential",1.2],["zoom"],11,0.5,20,6]}},{"id":"waterway_other","type":"line","source":"openmaptiles","source-layer":"waterway","filter":["all",["!=",["get","class"],"river"],["!=",["get","brunnel"],"tunnel"]],"layout":{"line-cap":"round"},"paint":{"line-color":"#a0c8f0","line-width":["interpolate",["exponential",1.3],["zoom"],13,0.5,20,6]}},{"id":"water","type":"fill","source":"openmaptiles","source-layer":"water","filter":["!=",["get","brunnel"],"tunnel"],"paint":{"fill-color":"rgb(158,189,255)"}},{"id":"landcover_sand","type":"fill","source":"openmaptiles","source-layer":"landcover","filter":["==",["get","class"],"sand"],"paint":{"fill-color":"rgba(247, 239, 195, 1)"}},{"id":"aeroway_fill","type":"fill","source":"openmaptiles","source-layer":"aeroway","minzoom":11,"filter":["match",["geometry-type"],["MultiPolygon","Polygon"],true,false],"paint":{"fill-color":"rgba(229, 228, 224, 1)","fill-opacity":0.7}},{"id":"aeroway_runway","type":"line","source":"openmaptiles","source-layer":"aeroway","minzoom":11,"filter":["all",["match",["geometry-type"],["LineString","MultiLineString"],true,false],["==",["get","class"],"runway"]],"paint":{"line-color":"#f0ede9","line-width":["interpolate",["exponential",1.2],["zoom"],11,3,20,16]}},{"id":"aeroway_taxiway","type":"line","source":"openmaptiles","source-layer":"aeroway","minzoom":11,"filter":["all",["match",["geometry-type"],["LineString","MultiLineString"],true,false],["==",["get","class"],"taxiway"Line truncated