feat(admin): comma-separated bulk add on the Blacklist page

The add-entry input took the whole field as one literal value, so
typing "word1, word2" created a single entry matching that exact
phrase instead of two separate words. Splits on comma client-side and
calls the existing single-value createBlacklistEntry mutation once
per value (dedup'd), with one consolidated toast instead of one per
word. No backend change — reuses the existing retroactive-scan
mutation as-is.

src/app/p/[secret]/blacklist/page.tsx

@@ -40,22 +40,8 @@ export default function AdminBlacklistPage() {
     )
   );
 
-  const createMutation = useMutation(
-    trpc.admin.createBlacklistEntry.mutationOptions({
-      onSuccess: ({ hiddenCount }) => {
-        void qc.invalidateQueries({ queryKey: trpc.admin.listBlacklist.queryKey() });
-        setNewValue("");
-        if (hiddenCount > 0) {
-          toast.success(`Added — ${hiddenCount} existing post${hiddenCount !== 1 ? "s" : ""} hidden retroactively.`);
-        } else {
-          toast.success("Blacklist entry added.");
-        }
-      },
-      onError: (err) => {
-        toast.error(`Failed to add entry: ${err.message}`);
-      },
-    })
-  );
+  const createMutation = useMutation(trpc.admin.createBlacklistEntry.mutationOptions());
+  const [isBulkAdding, setIsBulkAdding] = useState(false);
 
   const deleteMutation = useMutation(
     trpc.admin.deleteBlacklistEntry.mutationOptions({
@@ -66,10 +52,45 @@ export default function AdminBlacklistPage() {
     })
   );
 
-  function handleCreate() {
-    const value = newValue.trim();
-    if (!value) return;
-    createMutation.mutate({ type: newType, value });
+  /**
+   * Comma-separated bulk add — splits on "," so pasting "word1, word2, word3"
+   * creates one entry per word instead of a single literal-phrase entry.
+   * Reuses the existing single-value createBlacklistEntry mutation (with its
+   * retroactive scan) once per word rather than a new batch endpoint.
+   */
+  async function handleCreate() {
+    const values = [...new Set(newValue.split(",").map((v) => v.trim()).filter(Boolean))];
+    if (values.length === 0) return;
+
+    setIsBulkAdding(true);
+    let addedCount = 0;
+    let hiddenTotal = 0;
+    let failedCount = 0;
+
+    for (const value of values) {
+      try {
+        const { hiddenCount } = await createMutation.mutateAsync({ type: newType, value });
+        addedCount++;
+        hiddenTotal += hiddenCount;
+      } catch {
+        failedCount++;
+      }
+    }
+
+    setIsBulkAdding(false);
+    void qc.invalidateQueries({ queryKey: trpc.admin.listBlacklist.queryKey() });
+    setNewValue("");
+
+    if (addedCount > 0) {
+      const suffix =
+        hiddenTotal > 0
+          ? ` — ${hiddenTotal} existing post${hiddenTotal !== 1 ? "s" : ""} hidden retroactively.`
+          : "";
+      toast.success(`${addedCount} ${addedCount !== 1 ? "entries" : "entry"} added.${suffix}`);
+    }
+    if (failedCount > 0) {
+      toast.error(`${failedCount} ${failedCount !== 1 ? "entries" : "entry"} failed to add.`);
+    }
   }
 
   return (
@@ -79,6 +100,7 @@ export default function AdminBlacklistPage() {
         <p className="text-sm text-zinc-500 mt-1">
           Words, links, and hashtags that auto-hide matching posts — new posts are checked on
           creation, and adding an entry here retroactively scans + hides existing matches.
+          Separate multiple values with a comma to add them all at once.
         </p>
       </div>
 
@@ -96,19 +118,25 @@ export default function AdminBlacklistPage() {
         </Select>
         <Input
           placeholder={
-            newType === "WORD" ? "word…" : newType === "LINK" ? "domain, e.g. spam.example" : "hashtag (without #)"
+            newType === "WORD"
+              ? "word1, word2, …"
+              : newType === "LINK"
+                ? "domain1.example, domain2.example, …"
+                : "tag1, tag2 (without #)"
           }
           value={newValue}
           onChange={(e) => setNewValue(e.target.value)}
-          onKeyDown={(e) => e.key === "Enter" && handleCreate()}
+          onKeyDown={(e) => {
+            if (e.key === "Enter") void handleCreate();
+          }}
           className="flex-1 min-w-[200px] bg-zinc-800 border-zinc-700 text-zinc-100 placeholder:text-zinc-500"
         />
         <Button
-          onClick={handleCreate}
-          disabled={createMutation.isPending || !newValue.trim()}
+          onClick={() => void handleCreate()}
+          disabled={isBulkAdding || !newValue.trim()}
           className="bg-zinc-700 hover:bg-zinc-600"
         >
-          {createMutation.isPending ? (
+          {isBulkAdding ? (
             <Loader2 className="h-4 w-4 animate-spin mr-1.5" />
           ) : (
             <Plus className="h-4 w-4 mr-1.5" />