polish(desktop): name React Native apps in per-app labels

[janicduplessis]

Description

In a worktree with several apps, the log viewer App picker, the worktree page and the sidebar row name each app by its platforms only. In the stim repo the picker read "macOS" and "iOS · Android", which looked like a grouped platform filter rather than two apps.

Solution

An app that runs on iOS and/or Android is labelled "React Native" in place of those platforms. Any macOS or Web platform follows it ("React Native · Web"), and the folder suffix when two apps get the same label is unchanged ("React Native · apps/a"). The status payload has no framework field, so the label still comes from the platform set. Single-app worktrees show no picker and are unchanged. The phone app mirrors the rule in apps/mobile/src/lib/worktree-page.ts and both read the shared worktree-page-vectors.json, which is updated in place.

Polish change (copy only), collected under #3065.

Test plan

• Ran this worktree's Desktop with stim macos and drove it with agent-device (--surface app); stim logs --source agent lists the taps and snapshots.
• Log viewer App picker, open: lists "macOS" and "React Native".

• Inspector Build section and the Build sheet: platform rows and tabs are unchanged.

• pnpm test src/lib/worktree-page.test.ts in apps/mobile passes against the updated vectors; Desktop's WorktreePageTests reads the same file and runs in CI.
• Not checked live: the worktree "..." menu, the inspector Metro section and the sidebar row problem text, which use the same label function.

Fixes #3065