Support Ctrl+[ as an alternate Escape in vim insert mode

Feature request

In vim mode, Escape is the only way to leave INSERT mode and return to NORMAL mode. Vim users conventionally also use Ctrl+[ for this — it's a very common muscle-memory binding since it's closer to the home row than the physical Escape key.

Ctrl+[ and Escape send the identical byte (0x1B) at the raw terminal level, but Claude Code's vim-mode INSERT→NORMAL transition currently doesn't respond to it (only the actual Escape keypress works).

The existing vimInsertModeRemaps setting (v2.1.208+) only supports two-printable-character sequences (e.g. jj, kk) mapped to <Esc> — it can't express a Ctrl+key chord.

Request: Either make Ctrl+[ work as Escape in vim INSERT mode by default (standard vim behavior), or extend vimInsertModeRemaps (or a similar setting) to accept single Ctrl+key bindings as an escape trigger.

Environment: Claude Code v2.1.206, macOS.