fix(email): restore the sender identity when reopening a draft

Reopening a draft reset the composer's From to the default identity. The
edit-draft handler matched the draft's saved From against the active-account
identity list by email only, so two identities sharing an address (a default +
an alias differing by name) collided — the wrong one was picked, or with
cross-account namespaced ids none was.

Add findDraftIdentityId (name+email, normalized, +tag fallback) and match against
the same list the composer renders (the flat cross-account list when multi-
account is on). Wired into both the classic and Pro edit-draft paths. Unit tests
plus the un-pinned 07-drafts integration spec.

lib/__tests__/reply-identity.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest';
-import { findComposeIdentityId, findReplyIdentityId, resolveReplyFrom } from '../reply-identity';
+import { findComposeIdentityId, findDraftIdentityId, findReplyIdentityId, resolveReplyFrom } from '../reply-identity';
 import type { Identity } from '../jmap/types';
 
 const identities: Identity[] = [
@@ -17,6 +17,36 @@ const identities: Identity[] = [
   },
 ];
 
+describe('findDraftIdentityId', () => {
+  // Two identities on the SAME address, differing only by display name — the
+  // reopen-draft regression: an email-only match picks the default, not the one
+  // the draft was written with.
+  const sameAddress: Identity[] = [
+    { id: 'default', name: 'Harry Primary', email: 'harry@primary.com', mayDelete: false },
+    { id: 'team', name: 'Harry Team', email: 'harry@primary.com', mayDelete: false },
+  ];
+
+  it('restores the exact identity by name when several share an address', () => {
+    expect(findDraftIdentityId(sameAddress, { name: 'Harry Team', email: 'harry@primary.com' })).toBe('team');
+    expect(findDraftIdentityId(sameAddress, { name: 'Harry Primary', email: 'harry@primary.com' })).toBe('default');
+  });
+
+  it('matches by email (normalized) when the name is absent or unique', () => {
+    expect(findDraftIdentityId(identities, { email: 'HARRY@Secondary.com' })).toBe('secondary');
+    expect(findDraftIdentityId(identities, { name: 'Whatever', email: 'harry@secondary.com' })).toBe('secondary');
+  });
+
+  it('falls back to the +tag-stripped base address', () => {
+    expect(findDraftIdentityId(identities, { email: 'harry+promo@secondary.com' })).toBe('secondary');
+  });
+
+  it('returns null when nothing matches or there is no From', () => {
+    expect(findDraftIdentityId(identities, { email: 'nobody@elsewhere.com' })).toBeNull();
+    expect(findDraftIdentityId(identities, null)).toBeNull();
+    expect(findDraftIdentityId([], { email: 'harry@primary.com' })).toBeNull();
+  });
+});
+
 describe('findReplyIdentityId', () => {
   it('matches the identity that received the original message', () => {
     const selected = findReplyIdentityId(identities, {