Wrap parsePatch calls in try-catch blocks to gracefully handle malformed
diffs that can occur when undoing after tool_use/tool_result errors or
cancelled prompts. Prevents TUI from crashing with 'Added line count did not
match for hunk' error.
Fixes#3700
Users can now select models with multiple slashes like 'openrouter/google/gemini-2.5-pro'
in the TUI. Previously the TUI would only parse the first two parts of the model
path, showing 'Invalid model openrouter/google' for nested models.