feat(email): each account gets its own email, in its own zone (milestone 495)

Milestone 495 "Email goes to each account, in its own time zone", on the
operator's ruling (System 156): notifications go to each user, times in
their zone, defaults on, toggled per user or per role.

- users.notify_alerts / notify_report (migration 0036): None follows the
  role's default, notify.<kind>.<role> in settings, all on to start.
- mail.pick_recipients: active accounts that want the email and have an
  address mail can reach (an SSO placeholder like name@oidc is skipped and
  flagged), each in its own zone with no UTC beside it, then the Also send
  to addresses in their chosen zone with UTC beside. One copy per address,
  all over one SMTP connection.
- Alerts, the weekly report and the test email (to you, in your zone, plus
  the typed addresses) send that way. The save-time smtp.tz capture is gone.
- Notifications: a role × email table of defaults, who each email reaches
  and who can't be reached, and Also send to with its own zone, which starts
  as the first admin's to open the page.
- Account page: your address and your two switches. Users: an Emailed
  column, and an admin sets an account's switches on its page.
- The Alerts page counts the accounts it emails. zone_select macro and
  formatting.zones_by_region shared by Account and Notifications.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/integration/test_users_page.py

@@ -168,3 +168,33 @@ def test_only_an_admin_reaches_users(app):
         assert (await client.post("/settings/users/new", headers=CSRF, form={})).status_code == 403
 
     asyncio.run(_go())
+
+
+def test_an_account_sets_its_own_address_and_switches_and_an_admin_can_too(app):
+    async def _go():
+        viewer, vid = await _client(app, role="viewer")
+        page = await (await viewer.get("/account/")).get_data(as_text=True)
+        assert 'action="/account/email"' in page and "As for viewers (on)" in page
+
+        resp = await viewer.post("/account/email", headers=CSRF, form={
+            "email": "nope@oidc", "notify_alerts": "off", "notify_report": ""})
+        assert resp.status_code == 400 and "mail can reach" in await resp.get_data(as_text=True)
+        address = f"v-{vid[:8]}@example.com"
+        assert (await viewer.post("/account/email", headers=CSRF, form={
+            "email": address, "notify_alerts": "off", "notify_report": ""})).status_code == 302
+        me = await _user(app, vid)
+        assert (me.email, me.notify_alerts, me.notify_report) == (address, False, None)
+        assert [a for a, _ in await _audits(app, vid)] == ["account.email"]
+
+        admin, aid = await _client(app)
+        resp = await admin.post(f"/settings/users/{vid}/email", headers=CSRF,
+                                form={"email": "ignored@example.com", "notify_alerts": "", "notify_report": "off"})
+        assert resp.status_code == 302
+        me = await _user(app, vid)
+        assert (me.email, me.notify_alerts, me.notify_report) == (address, None, False)  # address kept
+        assert [a for a, _ in await _audits(app, aid)] == ["user.email_settings"]
+
+        page = await (await admin.get("/settings/notifications/")).get_data(as_text=True)
+        assert "Who gets email" in page and 'name="notify.alerts.viewer"' in page and "Also send to" in page
+
+    asyncio.run(_go())