Shared calendars in the calendar, and no more account switcher

Three things from using it on two real accounts.

A calendar shared with you never appeared. Nothing was wrong with the
share -- the calendar had nowhere to be shown. Calendars loaded from one
account and one only, so the sharer's were reachable solely by switching
the whole app to their account, which is the door being closed below.
They now sit under "Shared with me" beside the reader's own, in their own
colour, with their events in the grid and a click to hide them like any
other calendar.

Their events go through `instancesIn`, the one funnel every view already
reads, so month, week, day and agenda got them without being touched.
Events and calendars from another account are keyed by account as well as
id, and hiding one is remembered under the same key: an id means nothing
outside the account holding it, and two accounts sharing an id is
ordinary rather than unlucky.

An account that shared nothing was listed in Files as though it had.
Every non-personal account was offered on the reasoning that its folders
could speak for themselves -- but an account whose *calendar* was shared
has no folders to speak with, and appeared as an invitation to open an
empty pane. Each is now asked for one file before being listed, and
silence is taken for an answer.

And the account switcher is gone from the profile menu. It existed to
reach what other people shared and was the wrong door: it moved the whole
app to somebody else's account, and since Stalwart advertises every
capability on a shared account, mail, calendar and contacts went with it
and were refused. Everything it was for is now in the module the share
belongs to, found without anyone needing to know an account was involved.

What this does not prove is that Stalwart delivers a calendar share at
all. The mock says the client handles one, which is the half that was
missing; whether the server behaves like address books, which work, or
like mail folders, which do not, needs the two accounts again.

web/src/views/AppShell.tsx

@@ -6,7 +6,7 @@ import { toggleTarget, useEffectiveTheme, useSettings } from "@/store/settings";
 import { useMail } from "@/store/mail";
 import { draftFromMailto, useCompose } from "@/store/compose";
 import { Avatar, useIsMobile } from "@/ui/misc";
-import { MenuItem, MenuSep, MenuTitle, Popover, useMenu } from "@/ui/popover";
+import { MenuItem, MenuSep, Popover, useMenu } from "@/ui/popover";
 import { SearchBar } from "./SearchBar";
 import { MailboxTree } from "./mail/MailboxTree";
 import { FilesTree } from "./files/FilesTree";
@@ -14,7 +14,6 @@ import { ContactsSidebar } from "./contacts/ContactsSidebar";
 import { CalendarSidebar } from "./calendar/CalendarSidebar";
 import { ShortcutsDialog, useGlobalShortcuts } from "./Shortcuts";
 import { formatSize } from "@/lib/format";
-import { CAP } from "@/jmap/client";
 
 const PUSH_LABEL = {
   connected: "Live updates connected",
@@ -32,8 +31,6 @@ export function AppShell({ children }: { children: ReactNode }) {
   const openCompose = useCompose((s) => s.open);
   const pushState = useSession((s) => s.pushState);
   const session = useSession((s) => s.session);
-  const accountId = useSession((s) => s.accountId);
-  const setAccount = useSession((s) => s.setAccount);
   const logout = useSession((s) => s.logout);
   const acctMenu = useMenu();
   const section = location.split("/")[1] || "mail";
@@ -55,8 +52,16 @@ export function AppShell({ children }: { children: ReactNode }) {
     }
   }, [openCompose, navigate]);
 
-  const accounts = session ? Object.entries(session.accounts) : [];
-  const mailAccounts = accounts.filter(([, a]) => CAP.mail in (a.accountCapabilities ?? {}));
+  /*
+   * There is no account switcher any more.
+   *
+   * It existed to reach what other people shared, and was the wrong door: it
+   * moved the whole app to somebody else's account, and Stalwart advertises
+   * every capability on a shared account, so mail, calendar and contacts went
+   * with it and were refused. Shares are listed where they belong now -- in
+   * Files and in Contacts, beside the reader's own -- and found without anyone
+   * having to know an account switch was involved.
+   */
 
   return (
     <div className="app">
@@ -67,7 +72,7 @@ export function AppShell({ children }: { children: ReactNode }) {
         <Link href="/mail" className="brand">
           <img src="/img/logo.png" alt="" />
           <span className="brand-name">
-            ihasmail{mailAccounts.length > 1 ? "" : ""}
+            ihasmail
           </span>
         </Link>
         <SearchBar />
@@ -95,15 +100,6 @@ export function AppShell({ children }: { children: ReactNode }) {
                 <div className="hint truncate">{session?.ihasmail?.loginName}</div>
               </div>
             </div>
-            {mailAccounts.length > 1 && (
-              <>
-                <MenuSep />
-                <MenuTitle>Accounts</MenuTitle>
-                {mailAccounts.map(([id, a]) => (
-                  <MenuItem key={id} checked={id === accountId} label={a.name} onClick={() => setAccount(id)} />
-                ))}
-              </>
-            )}
             <MenuSep />
             <MenuItem icon={<Settings size={16} />} label="Settings" onClick={() => navigate("/settings")} />
             <MenuItem icon={<RefreshCw size={16} />} label="Refresh" onClick={() => window.location.reload()} />