long press account switch

[zoom-ua]

@mmaxim @chrisnojima

[Copilot]

Pull request overview

Adds a “long press to switch accounts” affordance to the native navigation header avatar, including remembering/restoring the previously-selected tab after an account switch on mobile.

Changes:

• Introduces shared account-switch utilities (MRU selection + pending tab remember/consume/clear) with unit tests.
• Adds a native header avatar component that supports press (open switcher) and long-press (switch to most-recent account), and wires it into the native stack header options.
• Adjusts People and Files headers to use the new shared header avatar behavior/components.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
shared/router-v2/router.tsx	Adds native header-left avatar on root screens and consumes/clears pending post-switch tab selection on navigation ready.
shared/router-v2/account-switcher/index.tsx	Remembers the current tab before initiating a mobile account switch via the account switcher UI.
shared/router-v2/account-switch.tsx	New helpers for MRU account selection and storing/consuming a pending tab to restore after account switch.
shared/router-v2/account-switch.test.tsx	Unit tests for MRU selection and pending-tab behavior.
shared/router-v2/account-switch-header-avatar.native.tsx	New native header avatar with press-to-open and long-press-to-switch-to-MRU behavior (with haptics + a11y strings).
shared/router-v2/account-switch-header-avatar.desktop.tsx	Desktop stub for the header avatar module.
shared/people/routes.tsx	Removes per-route header avatar now handled at the router header level.
shared/fs/nav-header/mobile-header.tsx	Adds the header avatar into the custom Android Files header layout and keeps the title centered via spacing.