[Bug] Scroll hint "jump to bottom ↓" corrupts copied text when selecting from scrollback

Bug Description

Problem

The "jump to bottom ↓" hint injects itself into copied text, but only when selecting while scrolled up. Selections made while scrolled to the bottom are clean.

Repro

1. Have a long conversation in Claude Code TUI
2. Scroll UP in the terminal
3. Select a multi-line block of text from the scrollback
4. Copy and paste elsewhere
5. Observe: "Jump to bottom ↓" appears injected into every line of the pasted output, overlaying the original characters at that column

Contrast:

• If you scroll back DOWN first, then select, the copied text is clean.
• Only selections made while the viewport is scrolled up are corrupted.

Expected

The scroll hint should not be part of the selectable/copyable text buffer. Either render it outside the scrollback region, or add a setting (e.g. ui.hideScrollHint: true) to disable it entirely.

Impact

Makes it impossible to reliably copy context from an earlier part of a session to paste into another session or document, unless you first scroll all the way back to the bottom — which defeats the purpose of scrolling up to find the content.

Environment

• Claude Code on macOS (Darwin 25.3.0), zsh
• Terminal: [fill in]

Environment Info

• Platform: darwin
• Terminal: iTerm.app
• Version: 2.1.101
• Feedback ID: 423841f0-afae-4b84-9d29-12a897167c7b

Errors

[{"error":"Error: NON-FATAL: Lock acquisition failed for /Users/seongyongpark/.local/share/claude/versions/2.1.101 (expected in multi-process scenarios)\n    at Oc_ (/$bunfs/root/src/entrypoints/cli.js:2836:2153)\n    at Ve6 (/$bunfs/root/src/entrypoints/cli.js:2836:1233)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-04-11T13:58:41.667Z"},{"error":"Error: Plugin MCP server error - mcp-config-invalid: MCP server github invalid: Missing environment variables: GITHUB_PERSONAL_ACCESS_TOKEN\n    at cYH (/$bunfs/root/src/entrypoints/cli.js:1555:33932)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-04-11T13:58:41.698Z"},{"error":"Error: Plugin MCP server error - mcp-config-invalid: MCP server sonatype-guide invalid: Missing environment variables: SONATYPE_GUIDE_TOKEN\n    at cYH (/$bunfs/root/src/entrypoints/cli.js:1555:33932)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-04-11T13:58:41.698Z"},{"error":"Error: Plugin MCP server error - mcp-config-invalid: MCP server sonatype-guide invalid: Missing environment variables: SONATYPE_GUIDE_TOKEN\n    at cYH (/$bunfs/root/src/entrypoints/cli.js:1555:33932)\n    at async Z (/$bunfs/root/src/entrypoints/cli.js:6003:11366)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-04-11T13:58:42.020Z"},{"error":"Error: Plugin MCP server error - mcp-config-invalid: MCP server github invalid: Missing environment variables: GITHUB_PERSONAL_ACCESS_TOKEN\n    at cYH (/$bunfs/root/src/entrypoints/cli.js:1555:33932)\n    at async Z (/$bunfs/root/src/entrypoints/cli.js:6003:11366)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-04-11T13:58:42.020Z"},{"error":"Error: Plugin MCP server error - mcp-config-invalid: MCP server sonatype-guide invalid: Missing environment variables: SONATYPE_GUIDE_TOKEN\n    at cYH (/$bunfs/root/src/entrypoints/cli.js:1555:33932)\n    at async W (/$bunfs/root/src/entrypoints/cli.js:6003:10596)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-04-11T13:58:42.021Z"},{"error":"Error: Plugin MCP server error - mcp-config-invalid: MCP server github invalid: Missing environment variables: GITHUB_PERSONAL_ACCESS_TOKEN\n    at cYH (/$bunfs/root/src/entrypoints/cli.js:1555:33932)\n    at async W (/$bunfs/root/src/entrypoints/cli.js:6003:10596)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-04-11T13:58:42.021Z"},{"error":"Error: Request was aborted.\n    at pE_ (/$bunfs/root/src/entrypoints/cli.js:1268:12089)\n    at next (native:1:11)\n    at sm7 (/$bunfs/root/src/entrypoints/cli.js:7918:9109)\n    at next (native:1:11)\n    at Hp7 (/$bunfs/root/src/entrypoints/cli.js:7923:11439)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-04-11T13:59:57.225Z"},{"error":"AxiosError: Request failed with status code 404\n    at eg (/$bunfs/root/src/entrypoints/cli.js:108:1194)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:113:12750)\n    at emit (node:events:92:22)\n    at endReadableNT (internal:streams/readable:865:50)\n    at processTicksAndRejections (native:7:39)\n    at request (/$bunfs/root/src/entrypoints/cli.js:115:2467)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-04-11T14:03:15.716Z"}]