fix: minor issues with fish's vim mode(s)

[rightaditya]

This PR fixes two minor issues when using Atuin with fish's vim mode(s):

1. Add support for fish_hybrid_key_bindings: in addition to fish_vi_key_bindings, fish also provides fish_hybrid_key_bindings, which is a vi-based mode with some extra keybinds; but the key bind check for atuin search only checks for the former.
2. The AI keybind inserts a ? on the command line in vim mode even though it can only be called from normal mode, when pressing ? normally does nothing.

Checks

• I am happy for maintainers to push small adjustments to this PR, to speed up the review cycle
• I have checked that there are no existing pull requests for the same thing

[greptile-apps]

Greptile Summary

Two targeted fixes for fish vim mode compatibility: adds fish_hybrid_key_bindings alongside fish_vi_key_bindings in _atuin_search (clearly correct), and stops the AI ? keybind from inserting a literal ? in vim normal mode by gating insertion on fish_default_key_bindings.

• atuin.fish: straightforward one-line fix, no issues.
• init.rs: the guard works correctly for the three standard binding styles, but the positive check for fish_default_key_bindings will silently discard ? for users with custom emacs-style bindings; checking for the absence of vi-based bindings instead would be more robust.

Confidence Score: 5/5

Safe to merge; both fixes are correct for all standard fish key binding modes.

Only finding is a P2 edge case affecting users with custom emacs-style key bindings, which is not a blocker.

crates/atuin-ai/src/commands/init.rs — the else if condition for ? insertion.

Important Files Changed

Filename	Overview
crates/atuin/src/shell/atuin.fish	Adds fish_hybrid_key_bindings to the vi mode case in _atuin_search so vim-normal/insert keymap modes are reported correctly for that binding style too.
crates/atuin-ai/src/commands/init.rs	Fixes spurious ? insertion in vim normal mode by only inserting when fish_default_key_bindings is active; custom non-vi binding users will silently lose ? insertion in non-empty buffers.

_{Reviews (1): Last reviewed commit: "fix: Detect both vim modes included in f..." | Re-trigger Greptile}

[rightaditya]

Friendly ping