Add hyperlink support (blocked on ratatui 0.30)

[ryanoneill]

Context

From user feedback: hyperlink support was requested but is blocked on ratatui 0.30, which adds the necessary hyperlink primitives. Envision currently depends on ratatui 0.29.

Constraint

Envision must stay on ratatui 0.29 for compatibility with a monorepo that has another application already using ratatui 0.29. Upgrading to 0.30 would cause a dependency conflict.

Options

1. Wait for the monorepo to upgrade — once the other application moves to ratatui 0.30, envision can follow
2. Implement hyperlinks without ratatui support — use OSC 8 escape sequences directly via crossterm, bypassing ratatui's rendering layer
3. Defer indefinitely — hyperlinks are a nice-to-have, not a blocker

Status

Blocked — not actionable until the ratatui 0.29 constraint is lifted.