[TUI] Long observation content truncated in detail view

[Twinber]

1. Problem statement: Observations with long lines or extensive markdown content (like image prompts or detailed logs) are being cut off at the terminal boundaries in the TUI detail view. This happens because the current implementation splits content by newlines but doesn't apply dynamic wrapping based on terminal width.

2. Proposed approach: Implement dynamic soft-wrapping in internal/tui/view.go using Lipgloss's Width().Render() capabilities. The content should be wrapped according to the window width (minus padding) before being split into lines for pagination/scrolling.

3. Risks/tradeoffs: Minimal. It might slightly change the line count for scrolling in very narrow terminals, but improves readability significantly.

4. Affected areas:

TUI (Observation Detail screen only).