feat(countries): replace Map view with browse-by-country (like Tags)

Removes the maplibre-gl Map view and adds "Countries" as a sixth
TagCategory, reusing the existing /tags/[category]/[[value]] browse
machinery instead of a bespoke map UI. Backed by a new self-contained
sidecar endpoint that aggregates photos.photo_country with BasePath
scoping, mirroring handleLabels/handleScopedCounts.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web/src/lib/components/sidebar/RightSidebar.svelte

@@ -6,7 +6,6 @@
 	PUT (Details fields need the full body).
 -->
 <script lang="ts">
-	import { goto } from '$app/navigation';
 	import { page } from '$app/state';
 	import { createMutation, createQuery, useQueryClient } from '@tanstack/svelte-query';
 	import { toast } from 'svelte-sonner';
@@ -16,10 +15,10 @@
 		Calendar,
 		File,
 		Folder,
+		Globe,
 		HardDrive,
 		ImageIcon,
 		Loader2,
-		Map as MapIcon,
 		MapPin,
 		Star,
 		Tag,
@@ -43,8 +42,9 @@
 	import { push as pushUndo } from '$lib/stores/undo.svelte';
 	import { getMetadataSectionOpen, setMetadataSection } from '$lib/stores/view.svelte';
 	import { photoNameAndDir, primaryFile, type PpPhoto } from '$lib/types/photoprism';
-	import { navigateToFolder } from '$lib/stores/filters.svelte';
+	import { navigateToFolder, navigateToTag } from '$lib/stores/filters.svelte';
 	import { COLOR_SWATCHES } from '$lib/utils/tagGroups';
+	import { countryName } from '$lib/utils/countries';
 	import { suggestDateFromPath } from '$lib/utils/suggestDateFromPath';
 
 	interface Props {
@@ -432,28 +432,22 @@
 			</span>
 		</div>
 
-		<!-- Location (read-only label + open-on-map icon). The arrow-up-
-		     right icon flies the in-app map to the photo's coordinates at
-		     zoom 17 (close enough for the photo's marker to be its own,
-		     out of any cluster). Hidden when the photo has no
-		     coordinates. -->
+		<!-- Location (read-only label + jump-to-country icon). Hidden when
+		     the photo has no resolved country. -->
 		<div class="flex items-center gap-2">
 			<MapPin class="h-3.5 w-3.5 shrink-0 text-muted-foreground" />
 			<span class="min-w-0 flex-1 truncate px-1 py-0.5 text-muted-foreground">
 				{placeLabel || 'No location'}
 			</span>
-			{#if photo.Lat && photo.Lng}
+			{#if photo.Country && photo.Country !== 'zz'}
 				<button
 					type="button"
 					class="text-muted-foreground hover:text-foreground"
-					onclick={() =>
-						void goto(
-							`/map?lat=${photo.Lat}&lng=${photo.Lng}&zoom=17&focus=${photo.UID}`
-						)}
-					title="Open on map"
-					aria-label="Open on map"
+					onclick={() => void navigateToTag('countries', photo.Country ?? null)}
+					title={`View other photos from ${countryName(photo.Country)}`}
+					aria-label={`View other photos from ${countryName(photo.Country)}`}
 				>
-					<MapIcon class="h-3 w-3" />
+					<Globe class="h-3 w-3" />
 				</button>
 			{/if}
 		</div>