Add session branch context and current diff review

[eivindjonassen]

Summary

• Show current branch context in the session shell, including loading, unavailable, no-branch, and stale states.
• Let users open branch and server details, copy their full names, and receive accessible copy feedback.
• Refresh location-scoped VCS state when vcs.branch.updated events arrive.
• Refine transcript summaries by intent: exploration, edits, shell commands, skills, and generic tools no longer collapse into one ambiguous Used group.
• Keep completed subagents and tool-only assistant metadata visually secondary while preserving running and failed states.
• Show the invoked command when shell output expands.
• Add Review current changes actions for edit tools.
• Add a native Current changes route backed by the OpenCode V2 working-tree diff operation.

Diff viewer

• Scope diff queries by connection, exact location, and diff mode.
• Render a virtualized unified diff with file status, aggregate additions and deletions, hunk styling, and selectable text.
• Bound files, lines, and line length before rendering on-device.
• Handle loading, empty, error, refresh, and connection-mismatch states.
• State explicitly that the screen shows the current working tree and may include edits made after the selected tool call.
• Keep file content out of navigation parameters and local persistence.

Supporting changes

• Add and validate the adapter operation for location-scoped VCS diffs.
• Extend deterministic HTTP fixtures with /api/vcs/diff behavior.
• Add navigation and query keys for the diff route.
• Add expo-clipboard for native branch and server name copying.
• Cover branch presentation, VCS event invalidation, transcript grouping, diff rendering, adapter validation, query isolation, and navigation with tests.

Verification

• pnpm check
• 49 mobile test suites, 265 tests
• iOS and Android Expo exports
• pnpm native:doctor, 18/18 checks passed