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, {

lib/reply-identity.ts

@@ -95,6 +95,45 @@ export function findComposeIdentityId(
   return baseIdentity?.id ?? null;
 }
 
+/**
+ * Restore the identity a draft was composed with from its saved From. A draft
+ * stores only the From address+name, not an identityId, so when two identities
+ * share an address (a default + an alias with a different display name) the name
+ * has to disambiguate — an email-only match picks the wrong one. Falls back to
+ * email, then `+tag`-stripped email. Returns null when none match (caller keeps
+ * the default). Pass the same identity list the composer renders (the flat
+ * cross-account list when multi-account is on) so the returned id is usable
+ * there.
+ */
+export function findDraftIdentityId(
+  identities: Identity[],
+  from?: { email?: string | null; name?: string | null } | null,
+): string | null {
+  const email = from?.email?.trim();
+  if (identities.length === 0 || !email) {
+    return null;
+  }
+
+  const wantEmail = normalizeEmailAddress(email);
+  const wantName = (from?.name ?? '').trim();
+
+  const nameAndEmail = identities.find(
+    (i) => normalizeEmailAddress(i.email) === wantEmail && (i.name ?? '').trim() === wantName,
+  );
+  if (nameAndEmail) {
+    return nameAndEmail.id;
+  }
+
+  const exact = identities.find((i) => normalizeEmailAddress(i.email) === wantEmail);
+  if (exact) {
+    return exact.id;
+  }
+
+  const wantBase = normalizeBaseEmailAddress(email);
+  const base = identities.find((i) => normalizeBaseEmailAddress(i.email) === wantBase);
+  return base?.id ?? null;
+}
+
 export interface ReplyFromResolution {
   /** Identity to use for JMAP `identityId` and the SMTP envelope MAIL FROM. */
   identityId: string;