Feature Parity: Advanced Chat Feed Elements

[vriesdemichael]

The mobile app lacks several rich elements found in the upstream web/desktop client's chat feed, specifically from packages/ui:

• ContextToolGroup: Collapsed grouping of file reads, glob searches, and list operations to save space.
• ToolStatusTitle & TextShimmer: Animated gradient text that says 'Gathering Context...' while tools run.
• DiagnosticsDisplay: Inline error reporting highlighting exact line/character coordinates for build failures or lints directly in the chat feed.
• ShellSubmessage: Smooth animated spring reveals for output from bash operations.
• DiffChanges: Interactive visual diffs of file patches applied by the agent before/after execution.