Add a blacklist editor that saves to e621

The Online sidebar's "Your blacklist" section is editable now: typing a
tag appends it and each entry gets an x to remove it. Changes are written
straight to the e621 account (PATCH /users/{id}.json with
user[blacklisted_tags]); the store keeps the fetched profile for the id,
updates the list optimistically and reloads it from e621. The Followed
page's blacklist cloud is rebuilt afterwards via the new
/api/follows/cloud/?refresh=1 force flag.

Verified against the live API with a reversible add/verify/restore test.

frontend/src/store/e621.ts

@@ -3,17 +3,21 @@ import { create } from "zustand";
 import { api } from "@/lib/api";
 import {
   effectiveCredentials,
+  updateBlacklist,
   verifyE621Credentials,
   type E621Credentials,
+  type E621User,
 } from "@/lib/e621";
 
 interface E621State {
   credentials: E621Credentials | null;
+  profile: E621User | null;
   blacklist: string[];
   loading: boolean;
   ready: boolean;
   load: () => Promise<void>;
   loadBlacklist: () => Promise<void>;
+  saveBlacklist: (lines: string[]) => Promise<void>;
   save: (values: {
     username: string;
     api_key: string;
@@ -24,6 +28,7 @@ interface E621State {
 
 export const useE621 = create<E621State>((set, get) => ({
   credentials: null,
+  profile: null,
   blacklist: [],
   loading: false,
   ready: false,
@@ -48,12 +53,23 @@ export const useE621 = create<E621State>((set, get) => ({
         .split("\n")
         .map((tag) => tag.trim())
         .filter(Boolean);
-      set({ blacklist: tags });
+      set({ blacklist: tags, profile: user });
     } catch {
       // Keep the last known blacklist when e621 is unreachable.
     }
   },
 
+  saveBlacklist: async (lines) => {
+    const credentials = get().credentials;
+    const profile = get().profile;
+    if (!credentials?.configured || !profile) {
+      throw new Error("Add e621 credentials in Account to edit your blacklist.");
+    }
+    await updateBlacklist(credentials, profile.id, lines.join("\n"));
+    set({ blacklist: lines });
+    await get().loadBlacklist();
+  },
+
   save: async (values) => {
     const credentials = await api<E621Credentials>("/api/auth/e621/", {
       method: "PUT",
@@ -64,5 +80,6 @@ export const useE621 = create<E621State>((set, get) => ({
     return credentials;
   },
 
-  clear: () => set({ credentials: null, blacklist: [], ready: false }),
+  clear: () =>
+    set({ credentials: null, profile: null, blacklist: [], ready: false }),
 }));