Print full PR URLs when OSC 8 hyperlinks are unsupported

[skarim]

• Closes gh stack: print full URL to stdout when terminal doesn't support OSC8 hyperlinks #183

Prints out full PR URLs on terminals that don't support OSC 8 hyperlinks.

Supported terminals keep the existing hyperlink behavior with printing PR references. When detected terminal doesn't support, fall back to printing the full URL (#N (full URL)). This covers gh stack view --short and existing non-TUI status output. TUI and JSON output behavior remains unchanged.

Detection is conservative for tmux, screen, Apple Terminal, Konsole, non-TTY output, and unknown terminals.
A GH_STACK_HYPERLINKS env var is available to override the detection — 1 forces hyperlinks and 0 forces full URLs.

[Copilot]

Pull request overview

Adds plain PR URL fallbacks when OSC 8 hyperlinks are unsupported.

Changes:

• Detects terminal hyperlink support with an environment override.
• Updates PR formatting and tests.
• Documents hyperlink behavior.

Show a summary per file

File	Description
README.md	Documents fallback behavior.
internal/config/config.go	Adds detection and URL formatting.
internal/config/hyperlink_test.go	Tests detection and formatting.
cmd/view_test.go	Tests short-view fallback.
docs/src/content/docs/reference/cli.md	Documents CLI behavior and environment variable.

Review details

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

• Files reviewed: 5/5 changed files
• Comments generated: 1
• Review effort level: Balanced