[BUG] Ghost-text "next action" suggestion visible, but Tab switches permission mode instead of accepting it

Description

When the input box shows a ghost-text "suggested next action" (grey, inline), pressing Tab does not accept the suggestion — it instead triggers permission-mode cycling (e.g. jumps to a different mode like Plan). This happens across practically every Desktop app session opened today, not an isolated instance.

Related but distinct from #79919 (suggestions never appear) and #76591 (users don't know Tab accepts them): here the suggestion does render correctly, but Tab is captured by mode-switching instead of accept, so the feature is unusable even by someone who already knows the intended shortcut.

Steps to reproduce

1. Open a Code session in the macOS Desktop app, in a git repo.
2. Wait for a grey ghost-text "next action" suggestion to appear in the input box (e.g. "confere se o túnel achou o Mac agora").
3. Press Tab.

Expected: the ghost-text suggestion is accepted into the input box.
Actual: the session's permission mode switches instead (observed going to a different mode than the one selected).

Environment

• Claude Desktop (macOS), version 1.34493.1
• macOS 27.0 (build 26A5416b)
• Observed in multiple concurrent sessions on the same machine on the same day, all in the same repo (git branch main), suggesting it isn't session- or repo-specific.
• No custom ~/.claude/keybindings.json present — default bindings only.

Impact

Ghost-text suggestions are effectively dead weight right now: the visual affordance invites Tab, but Tab does something else entirely, so the feature actively misleads rather than helps.