compose and add-account are real forms, so enter submits them

Compose's To/Cc/Bcc/Subject fields, and each of the three add-account
forms, sat in a plain div — enter did nothing and the button was the
only way in. Wrapped each in a <form onSubmit>, marked every button
that isn't the submit action type="button" (attach, cancel, cc/bcc
toggles, the recipient-suggestion picks), so none of them accidentally
submit now that a form exists around them. The compose body stays a
contenteditable div, which never triggers native enter-to-submit, so
Cmd/Ctrl+Enter wasn't needed to keep newlines working.

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

web/EmailAccounts.tsx

@@ -85,7 +85,8 @@ export const EmailAccounts = () => {
     }
   };
 
-  const handleGmailOAuth = async () => {
+  const handleGmailOAuth = async (ev?: React.FormEvent) => {
+    ev?.preventDefault();
     setSaving(true);
     try {
       const status = await client.get<{ connected: boolean; email: string | null }>('/integrations/google/status');
@@ -116,7 +117,8 @@ export const EmailAccounts = () => {
     }
   };
 
-  const handlePasswordSubmit = async () => {
+  const handlePasswordSubmit = async (ev?: React.FormEvent) => {
+    ev?.preventDefault();
     if (!form.email.trim() || !form.password.trim()) return;
     setSaving(true);
     try {
@@ -304,7 +306,10 @@ export const EmailAccounts = () => {
 
       {/* Gmail OAuth form */}
       {activeForm === 'gmail-oauth' && (
-        <div className="grid gap-3 rounded-lg border border-duck-dark/10 dark:border-foreground/10 p-4">
+        <form
+          onSubmit={handleGmailOAuth}
+          className="grid gap-3 rounded-lg border border-duck-dark/10 dark:border-foreground/10 p-4"
+        >
           <p className="text-sm font-medium text-duck-dark dark:text-foreground">Add Gmail (OAuth)</p>
           <input
             type="text"
@@ -317,16 +322,19 @@ export const EmailAccounts = () => {
             <Button type="button" variant="ghost" onClick={resetForm} className="h-9 cursor-pointer">
               Cancel
             </Button>
-            <Button type="button" onClick={handleGmailOAuth} disabled={saving} className="h-9 flex-1 cursor-pointer">
+            <Button type="submit" disabled={saving} className="h-9 flex-1 cursor-pointer">
               {saving ? <Loader2 className="h-4 w-4 animate-spin" /> : 'Connect & Add'}
             </Button>
           </div>
-        </div>
+        </form>
       )}
 
       {/* Gmail App Password form */}
       {activeForm === 'gmail-password' && (
-        <div className="grid gap-3 rounded-lg border border-duck-dark/10 dark:border-foreground/10 p-4">
+        <form
+          onSubmit={handlePasswordSubmit}
+          className="grid gap-3 rounded-lg border border-duck-dark/10 dark:border-foreground/10 p-4"
+        >
           <p className="text-sm font-medium text-duck-dark dark:text-foreground">Add Gmail (App Password)</p>
           <div className="text-xs text-duck-dark/50 dark:text-foreground/50 grid gap-1.5">
             <p>To create an App Password:</p>
@@ -373,20 +381,22 @@ export const EmailAccounts = () => {
               Cancel
             </Button>
             <Button
-              type="button"
-              onClick={handlePasswordSubmit}
+              type="submit"
               disabled={!form.email.trim() || !form.password.trim() || saving}
               className="h-9 flex-1 cursor-pointer"
             >
               {saving ? <Loader2 className="h-4 w-4 animate-spin" /> : 'Test & Save'}
             </Button>
           </div>
-        </div>
+        </form>
       )}
 
       {/* Generic IMAP form */}
       {activeForm === 'imap' && (
-        <div className="grid gap-3 rounded-lg border border-duck-dark/10 dark:border-foreground/10 p-4">
+        <form
+          onSubmit={handlePasswordSubmit}
+          className="grid gap-3 rounded-lg border border-duck-dark/10 dark:border-foreground/10 p-4"
+        >
           <p className="text-sm font-medium text-duck-dark dark:text-foreground">Add IMAP Account</p>
           <input
             type="email"
@@ -439,15 +449,14 @@ export const EmailAccounts = () => {
               Cancel
             </Button>
             <Button
-              type="button"
-              onClick={handlePasswordSubmit}
+              type="submit"
               disabled={!form.email.trim() || !form.password.trim() || !form.imapHost.trim() || saving}
               className="h-9 flex-1 cursor-pointer"
             >
               {saving ? <Loader2 className="h-4 w-4 animate-spin" /> : 'Test & Save'}
             </Button>
           </div>
-        </div>
+        </form>
       )}
 
       {/* Add account button */}