Prompt suggestions never appear (v2.1.296 / v2.1.300, Windows)

Since updating to v2.1.296 (now v2.1.300), the suggested next prompt (grey ghost text, accepted with → / Tab) no longer appears after any reply, in either the terminal CLI or the desktop app.

Checked:

• /config shows Prompt suggestions: true
• CLAUDE_CODE_ENABLE_PROMPT_SUGGESTION is not set in the environment
• No promptSuggestion* key in ~/.claude/settings.json or ~/.claude.json
• Restarted; tested over several turns that had an obvious follow-up

Debug log (claude --debug): the session made 4 source=repl_main_thread requests and no prompt-suggestion request at all, and nothing in the log mentions "suggestion". So the suggestion step never runs. It doesn't fail with an error.

Environment: Windows 11 Home 10.0.26300, PowerShell / Windows Terminal, Opus 5.5, Claude API, auto mode on.
Same version also introduced ← for agents on the empty prompt, in case the input keybinding changes are related.