feat: add bike-share and transit tools

Add get_bike_share over the public GBFS systems and get_transit_vehicles
over the GTFS-Realtime feeds. Each finds the systems or feeds whose
coverage reaches the area, reads up to three, and reports any that were
unavailable instead of failing the whole answer. Transit results carry
each feed's attribution and license.

docs/CURRENT-STATE.md

@@ -9,7 +9,8 @@ reading from a running app's `/api` routes (default `http://localhost:4173`).
 Queries cover earthquakes, active fires, recent launches, aircraft (in an
 area, by identifier, tracks, and type and route lookups), satellites (next
 pass over a point, and those overhead now), public cameras (including a
-camera's current image), radio stations, place search and routing. Tools reuse the layers' portable source factories, take a
+camera's current image), radio stations, place search, routing, bike-share
+stations and transit vehicles. Tools reuse the layers' portable source factories, take a
 shared `area` argument (place name, bounding box, or point and radius) and cap
 lists at 25 rows by default. The app does not import the tools, so its runtime
 behavior is unchanged. See [tools and the MCP server](TOOLS.md).