feat: quoted reply body and Forward button in email detail

Reply and reply-all now prefill the compose body with the original message
quoted as plain text (> lines). New Forward button sets Fwd: subject and
the same quoted body, leaving To/Cc empty for the user to fill.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

done.md

@@ -6,6 +6,12 @@ Tasks get moved from next.md to done.md
 
 ## Tasks
 
+## Quote original message in reply, and add Forward button
+
+`_reply` now passes `prefillBody` with the original message quoted as plain
+text (`> line…`). New `_forward` method and Forward toolbar button added;
+sets `Fwd:` subject prefix and prefills the same quoted body with To/Cc empty.
+
 ## Mark as unread button in email detail
 
 Added `mark_email_unread_outlined` icon button to `EmailDetailScreen` toolbar.

lib/ui/screens/email_detail_screen.dart

@@ -64,14 +64,21 @@ class _EmailDetailScreenState extends ConsumerState<EmailDetailScreen> {
                 tooltip: 'Reply',
                 onPressed: header == null
                     ? null
-                    : () => _reply(context, header, replyAll: false),
+                    : () => _reply(context, header, body, replyAll: false),
               ),
               IconButton(
                 icon: const Icon(Icons.reply_all),
                 tooltip: 'Reply all',
                 onPressed: header == null
                     ? null
-                    : () => _reply(context, header, replyAll: true),
+                    : () => _reply(context, header, body, replyAll: true),
+              ),
+              IconButton(
+                icon: const Icon(Icons.forward),
+                tooltip: 'Forward',
+                onPressed: header == null
+                    ? null
+                    : () => _forward(context, header, body),
               ),
               IconButton(
                 icon: const Icon(Icons.mark_email_unread_outlined),
@@ -228,7 +235,21 @@ class _EmailDetailScreenState extends ConsumerState<EmailDetailScreen> {
     );
   }
 
-  void _reply(BuildContext context, Email header, {required bool replyAll}) {
+  String _quotedBody(Email header, EmailBody? body) {
+    final date = header.sentAt != null ? _dateFmt.format(header.sentAt!) : '';
+    final from =
+        header.from.isNotEmpty ? header.from.first.toString() : '(unknown)';
+    final text = body?.textBody ?? htmlToPlain(body?.htmlBody ?? '');
+    final quoted = text.trim().split('\n').map((l) => '> $l').join('\n');
+    return '\n\n— On $date, $from wrote:\n$quoted';
+  }
+
+  void _reply(
+    BuildContext context,
+    Email header,
+    EmailBody? body, {
+    required bool replyAll,
+  }) {
     final to = header.from.isNotEmpty ? header.from.first.email : '';
     final subject = (header.subject?.startsWith('Re:') ?? false)
         ? header.subject!
@@ -241,12 +262,28 @@ class _EmailDetailScreenState extends ConsumerState<EmailDetailScreen> {
           'replyToEmailId': widget.emailId,
           'prefillTo': to,
           'prefillSubject': subject,
+          'prefillBody': _quotedBody(header, body),
           if (cc.isNotEmpty) 'prefillCc': cc,
         },
       ),
     );
   }
 
+  void _forward(BuildContext context, Email header, EmailBody? body) {
+    final subject = (header.subject?.startsWith('Fwd:') ?? false)
+        ? header.subject!
+        : 'Fwd: ${header.subject ?? ''}';
+    unawaited(
+      context.push(
+        '/compose',
+        extra: {
+          'prefillSubject': subject,
+          'prefillBody': _quotedBody(header, body),
+        },
+      ),
+    );
+  }
+
   Future<void> _moveTo(BuildContext context, Email header) async {
     final mailboxRepo = ref.read(mailboxRepositoryProvider);
     final mailboxes =

next.md

@@ -17,22 +17,3 @@ Git repo should not contain unknown files.
 Then commit.
 
 ## Tasks
-
-## Quote original message in reply, and add Forward button
-
-When replying, `prefillBody` is never set so compose opens with an empty body.
-Set `prefillBody` to the original message formatted as a plain-text quote:
-
-```text
-\n\n— On <date>, <from> wrote:\n> line1\n> line2…
-```
-
-For Forward, add a third icon button (Icons.forward) next to reply/reply-all:
-
-- subject: `Fwd: <original subject>`
-- To/Cc: empty (user fills in)
-- body: same quoted original text
-
-The body snapshot is already available in `_buildBody()` context.
-
-File: `lib/ui/screens/email_detail_screen.dart`