[BUG] TUI auto-links bare #number references to CWD repo instead of repo mentioned in context

Description

The Claude Code TUI auto-links any #<number> pattern (e.g., #1045, PR #1045) to the GitHub repo of the current working directory, even when the assistant is explicitly discussing a different repository. Full URLs work correctly, but bare references always resolve to the wrong repo.

Steps to Reproduce

1. Clone and cd into any repo, e.g. anthropics/claude-code
2. Ask Claude to mention a PR from a different repo. For example:

> "Please mention PR #100 from anthropics/anthropic-cookbook with the full URL https://github.com/anthropics/anthropic-cookbook/pull/100 and also as a bare #100 reference"

1. In the TUI output, hover over or click the links:

• The full URL (https://github.com/anthropics/anthropic-cookbook/pull/100) → links correctly to anthropic-cookbook
• PR #100 or bare #100 → links to https://github.com/anthropics/claude-code/issues/100 (the CWD repo)

Expected Behavior

Bare #number references should either:

• Not be auto-linked at all (safest — the assistant can always use full URLs), or
• Be resolved using surrounding context (repo name mentioned nearby)

Actual Behavior

All #<number> patterns are auto-linked to https://github.com/<cwd-owner>/<cwd-repo>/issues/<number>, regardless of which repository the assistant is discussing. This creates misleading clickable links that point to the wrong repo.

Impact

• Confusing UX when Claude discusses cross-repo PRs/issues
• Users may click and land on unrelated or nonexistent issues
• Particularly problematic for workflows that involve multiple repositories (monorepo tooling, cross-repo reviews, etc.)

Workaround

Always use full GitHub URLs instead of bare #number references when discussing cross-repo PRs/issues.

Environment

• Claude Code TUI (terminal)
• macOS (likely affects all platforms)