Home button fits all of Slovakia; add an overview map, top-right

Home now fitBounds()s a country-wide bbox instead of resetting to
CENTER/ZOOM's Bratislava point, since Home resetting into the same
city you'd already be looking at wasn't useful.

The overview map is NPS's own overview plugin (npmap5-plugins, still
on an unmerged branch), vendored and converted from its UMD dist
build to a plain ES module. Patched one MapLibre API break found while
verifying it: the plugin reads map.transform (public in the MapLibre
~2.4 it targets) to relax the inset's polar pan limit; MapLibre 6 (this
app's vendored version) no longer exposes .transform at all, so it
threw on load. Guarded to skip that cosmetic adjustment when absent
instead.

public/vendor/npmap-overview/LICENSE.md

@@ -0,0 +1,5 @@
+### LICENSE.md
+
+This project constitutes a work of the United States Government and is not subject to domestic copyright protection under [17 USC § 105](https://www.govinfo.gov/app/details/USCODE-2010-title17/USCODE-2010-title17-chap1-sec105).
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.