feat: implement mail account switcher

[AlexAndBear]

Description

Related Issue

• Fixes Mail: new account switcher #1678

How Has This Been Tested?

• test environment:
• test case 1:
• test case 2:
• ...

Types of changes

• Bugfix
• Enhancement (a change that doesn't break existing code or deployments)
• Breaking change (a modification that affects current functionality)
• Technical debt (addressing code that needs refactoring or improvements)
• Tests (adding or improving tests)
• Documentation (updates or additions to documentation)
• Maintenance (like dependency updates or tooling adjustments)

[Copilot]

Pull request overview

This PR replaces the vertical mail account list sidebar with a dropdown-based account switcher integrated into the mailbox tree. The new switcher provides a more compact UI by moving account selection from a dedicated sidebar to a button at the bottom of the mailbox navigation panel.

Key changes:

• Replaced MailAccountList component with new MailAccountSwitch component
• Removed the 100px-wide sidebar from the inbox layout
• Changed several async function signatures to return promises directly instead of being async functions

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
packages/web-app-mail/src/views/Inbox.vue	Removed MailAccountList component and its sidebar container from the inbox view
packages/web-app-mail/src/components/MailboxTree.vue	Added MailAccountSwitch component at the bottom of the mailbox tree container
packages/web-app-mail/src/components/MailAccountSwitch.vue	New dropdown-based account switcher with avatar, name, and email display
packages/web-app-mail/src/components/MailAccountList.vue	Removed the old vertical account list component
packages/web-app-mail/src/composables/useLoadMails.ts	Removed async keyword from loadMails function
packages/web-app-mail/src/composables/useLoadMailboxes.ts	Removed async keyword from loadMailboxes function
packages/web-app-mail/src/composables/useLoadMail.ts	Removed async keyword from loadMail function
packages/web-app-mail/src/composables/useLoadAccounts.ts	Removed async keyword from loadAccounts function

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[Copilot]

Potential runtime error if mailboxes array is empty after loading. Add a check to ensure the array has at least one element before accessing index 0.

Suggested change

	setCurrentMailbox(unref(mailboxes)[0])
	await loadMails(unref(currentAccount).accountId, unref(currentMailbox).id)
	if (unref(mailboxes) && unref(mailboxes).length > 0) {
	setCurrentMailbox(unref(mailboxes)[0])
	await loadMails(unref(currentAccount).accountId, unref(mailboxes)[0].id)
	} else {
	setCurrentMailbox(null)
	// Optionally handle the empty mailbox case here (e.g., show a message)
	}

[kulmann]

just noticing it here: could you add index.ts files which export all the files of a dir, so that we can merge multiple imports into one line? like we do it in all other apps and packages...

[kulmann]

Super shiny now, nice job! 😍