feat: Make it easier to handle multiple tags

- Tags can now be removed straight from the email header
- Tagging control now allows the user to (de)select multiple tags in one go

components/pro/pro-email-tab-body.tsx

@@ -16,6 +16,7 @@ import type { Email } from "@/lib/jmap/types";
 import { buildReplySubject, buildForwardSubject } from "@/lib/subject-prefix";
 import { getQuoteBodies } from "@/lib/email-composer-utils";
 import { buildForwardAsAttachmentPayload } from "@/lib/forward-as-attachment";
+import { KEYWORD_PREFIX, KEYWORD_PREFIX_LEGACY } from "@/lib/thread-utils";
 
 interface ProEmailTabBodyProps {
   tabId: string;
@@ -57,7 +58,6 @@ export function ProEmailTabBody({ tabId, data }: ProEmailTabBodyProps) {
   const moveToMailbox = useEmailStore((s) => s.moveToMailbox);
   const setEmailKeywordsLocal = useEmailStore((s) => s.setEmailKeywordsLocal);
   const mailboxes = useEmailStore((s) => s.mailboxes);
-  const settingsKeywords = useSettingsStore((s) => s.emailKeywords);
   const identities = useIdentityStore((s) => s.identities);
   const multiAccountIdentities = useProMultiAccountIdentities();
 
@@ -238,18 +238,29 @@ export function ProEmailTabBody({ tabId, data }: ProEmailTabBodyProps) {
 
   const handleSetTag = useCallback((emailId: string, tagId: string | null) => {
     if (!email || email.id !== emailId) return;
-    // Drop existing color keywords, optionally add the new one. Matches the
-    // mail page's local optimistic update.
+    // Toggle one tag, or clear them all. Matches the mail page's local
+    // optimistic update, down to reaching tags this client cannot name.
     const keywords = { ...(email.keywords ?? {}) };
-    for (const kw of settingsKeywords) {
-      delete keywords[`$label:${kw.id}`];
-    }
-    if (tagId) {
-      keywords[`$label:${tagId}`] = true;
+    if (tagId === null) {
+      for (const key of Object.keys(keywords)) {
+        if (key.startsWith(KEYWORD_PREFIX) || key.startsWith(KEYWORD_PREFIX_LEGACY)) {
+          keywords[key] = false;
+        }
+      }
+    } else {
+      const activeKeys = [KEYWORD_PREFIX + tagId, KEYWORD_PREFIX_LEGACY + tagId]
+        .filter(key => keywords[key]);
+      if (activeKeys.length > 0) {
+        for (const key of activeKeys) {
+          keywords[key] = false;
+        }
+      } else {
+        keywords[KEYWORD_PREFIX + tagId] = true;
+      }
     }
     setEmailKeywordsLocal(emailId, keywords);
     setEmail({ ...email, keywords });
-  }, [email, settingsKeywords, setEmailKeywordsLocal]);
+  }, [email, setEmailKeywordsLocal]);
 
   const handleMoveToMailbox = useCallback(async (mailboxId: string) => {
     if (!client || !email) return;