web: de-brand PhotoPrism references in user-facing copy

Replaces "PhotoPrism" in UI strings (empty states, tooltips, toasts,
log header, login screen) with neutral terms like "the indexer", "the
library", "the server" — accurate regardless of backend. The login
header becomes "Mulimage" and drops the explicit PhotoPrism mention.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

web/src/routes/+page.svelte

@@ -856,13 +856,13 @@
                 <EmptyState
                   icon={Sparkles}
                   title="Nothing left to review"
-                  description="Photos PhotoPrism's indexer wasn't sure about land here — use Keep to accept them into the timeline or Archive to set them aside."
+                  description="Photos the indexer wasn't sure about land here — use Keep to accept them into the timeline or Archive to set them aside."
                 />
               {:else if filters.section === "hidden"}
                 <EmptyState
                   icon={EyeOff}
                   title="No hidden photos"
-                  description="PhotoPrism auto-hides files it can't index (broken files, very low quality); they only ever show up here."
+                  description="The indexer auto-hides files it can't read (broken files, very low quality); they only ever show up here."
                 />
               {:else if filters.section === "heap"}
                 <EmptyState
@@ -874,7 +874,7 @@
                 <EmptyState
                   icon={ImageOff}
                   title="No photos"
-                  description="Index a folder via PhotoPrism's reindex command."
+                  description="Index a folder from Settings → Index, or run a reindex from the server."
                 />
               {/if}
             {:else}