fix: Pressing 'enter' after a suggested command inserts instead of runs in bash

[BinaryMuse]

The bash integration's __atuin_ai_execute__ branch set READLINE_LINE and then bound two key sequences that nothing ever invoked, so "execute" behaved identically to "insert": accepting an AI suggestion with enter just placed it in the buffer.

Readline provides no way to call accept-line from a shell function, so this uses the same string-macro trick as atuin.bash's enter_accept support: "?" is bound to a two-part macro where the first keyseq runs the widget via bind -x and the trailing keyseq is dynamically rebound to accept-line (execute) or a no-op (everything else). Under ble.sh the widget calls ble/widget/accept-line directly. Bash <= 4.2 can't bind -x multi-byte key sequences, so it keeps the direct binding and execute still degrades to insert there.

Also removes the dead __atuin_ai_accept_line /
_atuin_ai_question_mark_wrapper scaffolding.

[greptile-apps]

Greptile Summary

This PR fixes bash AI suggestions so execute suggestions can submit the command.

• Adds a readline macro chain for the ? AI binding.
• Rebinds the trailing macro key to accept-line only for execute suggestions.
• Calls ble/widget/accept-line directly when ble.sh is active.
• Keeps the older Bash fallback as insert-only behavior.

Confidence Score: 5/5

This looks safe to merge.

• No blocking issues found in the changed code.
• The macro flow matches the existing bash integration pattern.
• The ble.sh branch follows the existing accept-line handling style.

Important Files Changed

Filename	Overview
crates/atuin-ai/src/commands/init.rs	Updates the generated bash AI integration to use a macro-based accept-line flow, with a ble.sh-specific execute path and string checks in tests.

_{Reviews (1): Last reviewed commit: "Fix AI execute mode in bash: enter now r..." | Re-trigger Greptile}